Head and Neck Questions

327. A 13-month-old baby boy is brought into the pediatric office by his concerned mother. The boy is just beginning to talk and seems to have difficulty speaking some sounds. The mother also notes that his tongue seems "sort of stuck in his mouth" compared to her two older children. Examination of the baby, including his mouth, confirms that his tongue seems to be stuck in the floor of his mouth. Which one of the following is the correct explanation of this part of tongue development? a. The hypoglossal nerves that control the tongue failed to develop b. The problem could likely be corrected by cutting the lingual frenulum c. The problem could likely be corrected by shortening the posterior belly of the digastric muscle d. The problem could likely be corrected by cutting the pterygomandibular raphe e. The problem is not correctable and speech therapy is the best option

327. The answer is b. (Moore, p 950.) The pediatrician explains that the problem could be corrected by cutting the lingual frenulum. The boy is currently "tongue-tied." The frenulum of the tongue limits its ability to protrude from the mouth. The inferior aspect of the genioglossus and the geniohyoid muscles contract in order to pull the hyoid bone forward allowing one to stick their tongue out of their mouth. All the intrinsic and three quarters of the extrinsic muscles of the tongue are innervated by the hypoglossal nerve (XII CN). It is very unlikely that the XII cranial nerve never developed (answer a), since the child would then have no tongue movement and the tongue would atrophy. Shortening the posterior belly of the digastric (answer c) would worsen the problem by pulling the tongue up and back within the mouth. Cutting the pterygomandibular raphe (answer d) would serve no function. Speech therapy (answer e) would be the second best answer in that it might stretch the frenulum over time.

274. When a physician examines the "corneal reflex" in a patient, she/he touches the cornea with a wisp of cotton that causes the eyelid to rapidly shut. As with most reflexes, one is testing both the afferent information that is carried back to the central nervous system and the reflex motor response. What specific cranial nerve branches are responsible for both the afferent and efferent parts of the corneal reflex? a. Short ciliary nerve (CN III); zygomatic and temporal branches of the facial nerve (CN VII) b. Short ciliary nerve (CN III); oculomotor nerve (CN III) c. Long ciliary nerve (CN V1); zygomatic branches of the facial nerve (CN VII) d. Long ciliary nerve (CN V1); infraorbital branch of the trigeminal nerve (CN V2) e. Infraorbital nerve (CN V2); zygomatic branches of the facial nerve (CN VII)

274. The answer is c. (Moore, pp 903-905, 912.) During the corneal reflex the long ciliary (CN V1) nerve carries pain information from the eye, which causes the eye to close due to firing of the muscle of facial expression innervated by the zygomatic branch of the facial nerve (CN VII). Short ciliary nerves (answers a and b), by definition, have traveled through the ciliary ganglia (some have synapsed) and, therefore, are postganglionic parasympathetic fibers, which will innervate the intraocular eye muscles for accommodation of the iris and pupil. The infraorbital branch of CN V2 (answers d and e), while sensory, does not innervate the eye, but does innervate the skin and lower eyelid.

275. A 79-year-old man is brought to a family practice office by his wife because he "keeps running into things" on his right side. His wife also reports that he seems to ignore objects on his right. Testing his vision in each eye his physician determines that the patient cannot see anything in the right visual field of either eye. The physician orders a head MRI because he suspects which one of the following? a. A pituitary tumor compressing his optic chiasm b. A tumor in the medial wall of the right orbit compressing the optic nerve c. An aneurysm of the left middle cerebral artery compressing the left optic tract d. A tumor in the middle cranial fossa compressing the right optic tract e. An aneurysm in the arterial supply to the visual cortex

275. The answer is c. (Moore, pp 1061-1063, 1080. Fauci, pp 184-185.) Information from the nasal retinal field crosses the midline at the optic chiasm; thus images from the right visual fields strike the left retinal fields of both eyes and from the right eye cross at the optic chiasm (see High-Yield Facts, Figure 18, p 77). The images that strike the left temporal retina (from the right visual field) of the left eye stay on the left and join the nasal retinal field of the right eye in the left optic tract. An aneurysm in the left middle cerebral artery, if large enough, would likely impinge on the left optic tract. A pituitary tumor (answer a) would likely compress the optic chiasm leading to a loss of the temporal visual fields in both eyes (bilateral tunnel vision or bitemporal hemianopsia). A tumor in the right orbit that compresses the right optic nerve (answer b) would lead to loss of vision in only the right eye. Compromise of the right optic tract (answer d) would lead to loss of left visual fields in both eyes. An aneurysm affecting the arterial supply to the occipital visual

276. A 23-year-old woman presents with concern over a hyperpigmentation spot that has enlarged after her weeklong vacation in Cancun, Mexico. The woman is blond with fair skin. The pigmented spot is on her cheek, below the medial portion of her eye and lateral to the dorsal surface of the nose, but just above her labial malar (nasolabial) skin fold. The spot has grown to about 6 mm laterally and 4 mm cranially/caudally with irregular borders and two tones of brown pigmentation. What two regional lymph nodes should specifically be palpated during her physical examination? a. Buccal and submandibular nodes b. Buccal and submental nodes c. Jugulodigastric and juguloomohyoid nodes d. Parotid and mastoid nodes e. Submental and submandibular nodes

276. The answer is a. (Moore, pp 858-859.) The buccal and submandibular nodes should be specifically palpated. The hyperpigmentation lesion could be malignant melanoma, which can spread to regional lymph nodes. The spot is just above the nasolabial skin fold so it should drain first into buccal (or facial) lymph nodes, which then drain into submandibular lymph nodes. Submental nodes (answers b and e) receive lymph from the lower lip and chin area. Jugulodigastric and juguloomohyoid nodes (answer c) are named members of deep neck lymph nodes and would not be the first nodes to receive metastatic cells. The parotid and mastoid nodes (answer d) are just in front of and behind the ear, respectively and receive most of their lymph from the pinna of the ear or areas superior to this region.

277. The central nervous system is bathed in 135 to 150 mL of cerebrospinal fluid (CSF). In adults, this fluid is produced at the rate of 450 to 500 mL per day from the choroid plexus within the ventricular system and should have a pressure of less than 20 cm of water. Most of the absorption of cerebrospinal fluid occurs at arachnoid villi. The arachnoid villi allow cerebrospinal fluid to pass between which of the following two spaces? a. Choroid plexus and subdural space b. Subarachnoid space and subdural space c. Subarachnoid space and superior sagittal sinus d. Subdural space and cavernous sinus e. Superior sagittal sinus and jugular vein

277. The answer is c. (Moore, pp 866, 878-882.) Cerebrospinal fluid (CSF) formed in the choroid plexus circulates in the subarachnoid space and is absorbed by the venous sinuses through the arachnoid villi, some of which project into the superior sagittal sinus and its lateral lacunae. Lateral lacunae are areas of expansion of the superior sagittal sinus. CSF protects the nervous system during impact and against mechanical injuries and is important for metabolism. It circulates slowly through the ventricles of the brain, out of the fourth ventricle, and through the meshes of the subarachnoid space.

278. A 44-year-old attorney presents to a family practice office with a hat on her head and wearing dark sunglasses even though it is an overcast January day. Upon taking off her glasses and hat a series of vesicles are visible above her left eye continuing to her hairline. The vesicles stop at the midline of her forehead, but extend onto the dorsal surface of her nose and onto her left upper eyelid. There are no vesicles around or above her ears. She reports that she had pain in a similar pattern for a couple of days before the vesicles suddenly appeared. She can think of no change in habits or travel to account for the vesicles; she has infrequently left her home and office during the past 2 weeks since she is preparing for a case before the Cailfiornia Supreme Court. She had both chickenpox and mumps as a child. What is the working diagnosis and explanation for the unique pattern of the vesicles? a. Herpes zoster affecting the mandibular division of the trigeminal cranial nerve b. Herpes zoster affecting the ophthalmic division of the trigeminal cranial nerve c. Herpes zoster affecting the zygomatic branch facial cranial nerve d. Mumps affecting the maxillary division of the facial cranial nerve e. Mumps affecting her parotid salivary gland

278. The answer is b. (Moore, pp 96-97, 849-853.) The attorney is diagnosed with herpes zoster affecting the ophthalmic division of the trigeminal cranial nerve. Herpes zoster is the reemergence of varicella-zoster virus after it has lay dormant within the sensory ganglia (the trigeminal ganglia in this case). Herpes zoster produces pain and vesicles (shingles) along a dermatomal pattern. Her vesicle pattern matches the left ophthalmic division of the trigeminal cranial nerve. The trigeminal ganglia contain nerve cell bodies, which receive and transmit sensory information into the brain stem from the face. The mandibular division of the trigeminal cranial nerve (answer a) runs along the mandible and anterior to her ear along the side of her head. The zygomatic branch of the facial nerve (answer c) is a motor nerve, and these are not usually affected by varicella-zoster virus. Mumps is caused by the mumps virus and often causes painful swelling of the parotid salivary gland (answer d and e), which is unaffected in this woman. (Also see Question and Answer 137.)

302. An 87-year-old man had been sitting on the toilet when suddenly he fell to the left side against an adjacent wall. Fortunately his wife heard him hit his head against the tiled wall and found him partially wedged against it. While he is conscious, he has difficulty speaking and little control of his left side, though he is capable of some movement. The paramedics arrive, lift him from his stuck position, give him oxygen during the ambulance trip, hook up ECG leads, and find normal heart rhythm and patterns. By the time he arrives in the ED, he is a little more responsive, but his speech is slurred. A head CT is immediately performed and is read as normal other than slight age-associated shrinkage of the brain. He has a bad headache and stiff neck. There is no papilledema, so a spinal tap is performed to determine whether to start tissue plasminogen activator (TPA) treatment. There is some blood found equally within all four tubes collected, so TPA is not initiated. Which one of the following is the most likely diagnosis? a. Subarachnoid hemorrhagic stroke, which had stopped by the time the CT was performed b. Ischemic stroke, which had opened by the time the CT was performed c. Subdural hematoma d. Epidural hematoma e. Alzheimer dementia

302. The answer is a. (Moore, pp 887-888.) The most likely diagnosis is a subarachnoid hemorrhagic stroke, which had stopped by the time the CT was performed. While most strokes present with sudden onset of neurological symptoms, the majority of strokes (~80%) are ischemic (answer b) in nature due to cerebral blood clots. This man probably had a hemorrhagic stroke as a consequence of increased blood pressure due to straining, to relieve his constipation. This is consistent with his developing headache, stiff neck, and blood within the CSF collected by spinal tap. One would not want to give TPA to a patient with a hemorrhagic stroke because it would probably make conditions worse. The CT was normal because the blood vessel had spontaneously stopped bleeding and the amount of blood was too small to detect radiographically. Subdural hematoma (answer c), while common in the elderly, would not result in a bloody spinal tap. Epidural hematoma (answer d) would not result in a bloody spinal tap. Alzheimer dementia (answer e) is not relevant to this case.

279. A 28-year-old man is treated in the emergency department (ED) for a superficial gash on his forehead. The wound is bleeding profusely, but examination reveals no fracture. While the wound is being sutured, he relates that while he was using an electric razor, he remembers becoming dizzy and then waking up on the floor with "blood everywhere." The physician suspects a hypersensitive cardiac reflex. The patient's epicranial aponeurosis (galea aponeurotica) is penetrated, resulting in severe gaping of the wound. The structure overlying the epicranial aponeurosis is which one of the following? a. A layer containing blood vessels b. Bone c. The dura mater d. The periosteum (pericranium) e. The tendon of the epicranial muscles (occipitofrontalis)

279. The answer is a. (Moore, pp 843-844, 860.) A mnemonic device for remembering the order in which the soft tissues overlie the cranium is SCALP: skin, connective tissue, aponeurosis, loose connective tissue, and periosteum (answer d). The scalp proper is composed of the outer three layers, of which the connective tissue contains one of the richest cutaneous blood supplies of the body. The occipitofrontal muscle complex inserts into the epicranial aponeurosis, which forms the intermediate tendon of the digastric muscle (answer e). This structure, along with the underlying layer of loose connective tissue, accounts for the high degree of mobility of the scalp over the pericranium. If the aponeurosis is lacerated transversely, traction from the muscle bellies will cause considerable gaping of the wound. Secondary to trauma or infection, blood or pus may accumulate subjacent to the epicranial aponeurosis. Bone (answer b) is too deep, as is the dura mater (answer c).

280. A 52-year-old woman is referred to the dermatologist. Unlike many patients she is not concerned about the lines and wrinkles that are beginning to appear on her face, but she is concerned because she has been told repeatedly by friends that she looks "sad" recently. She has brought in a 10-year-old picture of herself. When examining her face you notice that the inferior corners of her mouth droop downward. Which muscle of facial expression will the dermatologist inject with botulinum toxin (Botox) to improve her smile? a. Depressor anguli oris muscle b. Mentalis muscle c. Orbicularis oculi muscle d. Orbicularis oris muscle e. Zygomaticus major muscle

280. The answer is a. (Moore, pp 844-849.) Botulinum toxin injection inhibits acetylcholine release at the neuromuscular junction, leading to flaccid (sagging) paralysis of muscle. If injected into the depressor anguli oris muscles at each corner of the mouth, the levator anguli oris and zygomaticus major muscles, which are unaffected, will better be able to lift the corners of her mouth, giving her a more youthful smile. The mentalis muscle (answer b) is more medial in location than the corner of the mouth and tends to pull the lower lips inferiorly and medially. The orbicularis oculi muscle (answer c) surrounds the eye and closes the eyes (producing "crow's feet" at the lateral canthus of the eye). The orbicularis oris muscle (answer d) surrounds the lips and allows them to close tightly as when kissing. The zygomaticus major muscle (answer e) tends to raise the corner of the mouth and upper lips and is needed for smiling, so it should not be injected.

281. A 19-year-old teenager comes into the emergency department (ED) at 5:00 PM with cotton in his nose and blood running down the front of his T-shirt nearly to his belt. He was in the ED the night before. The previous night, gauze soaked in procoagulant had stopped the problem, but not now. No history of trauma was reported. Upon removing the blood soaked gauze, blood pumped from an artery in Kiesselbach area, on the nasal septum, just superior and posterior to the external nasal aperture. An ENT was called in to cauterize the boy's nose. There are four major blood vessels that normally supply blood to the Kiesselbach area. Describe how, for at least two of the arteries, a physician can have the boy apply pressure elsewhere (not directly on the pulsating artery) that may successfully cut off blood to the pulsating artery, while the ENT cauterizes the blood vessel. a. Hold both sides of the bridge of the nose at the apex from the exterior. b. Hold both sides of the upper lip between his fingers. c. Hold both sides of the nose at the junction of the nasal bones with the lateral nasal cartilages. d. Apply pressure from the oral cavity over the incisive foramen. e. a and b f. b and d

281. The answer is f. (Moore, pp 959-960, 964.) Nosebleed blood flow to Kiesselbach area may be reduced by holding both sides of the upper lip and also pressing on the incisive foramen. Kiesselbach area on the nasal septum is just superior and posterior to the external nasal aperture. Many nose-bleeds (or epistaxis) occur in this area since it is exposed to most of the incoming air. There are four blood vessels that supply blood to this area: (1) anterior ethmoid artery (a branch off the ophthalmic artery); (2) sphenopalatine artery (a branch off the maxillary artery that exits the sphenopalatine foramen); (3) greater palatine artery (a branch also off the maxillary artery, but traverses both the greater foramen and the incisive foramen to reach the nose); and (4) septal branch artery (a branch off the superior labial artery which is derived from the facial artery). While the lay press often suggests holding the bridge of the nose (answers a and e), that would only block blood within the infratrochlear artery, which mainly serves the exterior dorsal surface of the nose. Holding (answer c) both sides of the nose at the junction of the nasal bones with the lateral nasal cartilages would tend to block blood flow within the external branch of the anterior ethmoid. This might actually increase the blood coming from an artery in Kiesselbach area. Thus (answer b) holding both sides of the upper lip between his fingers will cut off blood to the septal branch of the superior labial artery, and applying pressure from the oral cavity over the incisive foramen (answer d) would cut off blood coming from the greater palatine arteries. Note that it is difficult to stop blood within either the sphenoid palatine artery or anterior ethmoid arteries by applying any external pressure.

A 42-year-old Asian woman presents to her family practice physician with a bulge in the middle of her neck in front of her trachea. The growth has become bothersome when she swallows and has been noticed by family and friends. An ENT physician performs a fine-needle biopsy, taking samples from both the right and left side of the thyroid gland and sends the sample for pathological analysis. The pathology report is returned with a diagnosis of papillary thyroid cancer and the ENT recommends surgical removal of all of the thyroid gland. 282. What risk factors does the surgeon warn the patient about before reassuring the woman that he has removed hundreds of cancerous thyroid glands without such complications? a. Creation of a tracheostomy stoma for breathing and loss of peristaltic function due to cutting of the vagus nerve b. Creation of a tracheostomy stoma for breathing and placement of a gastric stoma to bypass loss of swallowing function c. Loss of peristaltic function due to cutting of the vagus nerve and hypoparathyroidism due to removal of the parathyroid glands d. Loss of voice due to creation of a tracheostomy stoma for breathing and loss of peristaltic function due to cutting of the vagus nerve e. Loss of singing voice due to cutting the recurrent laryngeal nerve and hypoparathyroidism due to removal of the parathyroid glands

282. The answer is e. (Moore, pp 1043-1046.) During removal of the thyroid gland the surgeon must be careful not to cut the recurrent laryngeal nerve and cause hypoparathyroidism by incidental removal of the parathyroid glands. The thyroid gland often wraps itself around the trachea within pretracheal fascia, and the recurrent laryngeal nerve runs alongside the trachea in between the trachea and the esophagus, so those nerves that control the larynx are at risk. The parathyroid glands normally lie on the deep surface of the thyroid gland and typically receive their blood supply from the inferior thyroid arteries. If all four of the parathyroid glands are removed then parathyroid hormone (PTH) would not be produced. PTH is essential for maintaining proper calcium levels and hypocalcemia and eventual tetany would result. Removal of the thyroid gland often decompresses the trachea, so creation of the tracheostomy (answers a and b) would rarely, if ever, be needed. The vagal nerves run as a plexus upon the esophagus, which is posterior to the trachea, so, rarely would a vagus nerve (answer c and d) or peristaltic function be at risk.

A 42-year-old Asian woman presents to her family practice physician with a bulge in the middle of her neck in front of her trachea. The growth has become bothersome when she swallows and has been noticed by family and friends. An ENT physician performs a fine-needle biopsy, taking samples from both the right and left side of the thyroid gland and sends the sample for pathological analysis. The pathology report is returned with a diagnosis of papillary thyroid cancer and the ENT recommends surgical removal of all of the thyroid gland. 283. Which muscles must be retracted to gain access to the thyroid gland during its removal? a. Longus coli, longus capitus, and anterior scalene muscles b. Mylohyoid, anterior belly of the digastrics, genioglossus, and geniohyoid muscles c. Platysma, sternohyoid, sternothyroid, and omohyoid muscles d. Superior, middle, and inferior pharyngeal constrictors e. Trapezius, rhomboids, and levator scapulae muscles

283. The answer is c. (Moore, pp 999-1001.) The platysma, and the strap muscles: sternohyoid, sternothyroid, and omohyoid would be retracted during thyroid gland removal. The thyroid gland lies in pretracheal fascia, which is deep to those four muscles. The sternocleidomastoid, and trapezius are within the investing fascia of the neck, which is superficial to both the thyroid gland (in pretracheal fascia) and in the infrahyoid strap muscles. The stern-ocleidomastoid muscle might also need to be retracted. The longus coli, longus capitus muscle, and anterior scalene muscles (answer a) are all anterior to the vertebral column surrounded by prevertebral fascia and are posterior to the thyroid gland. The mylohyoid, anterior belly of the digastrics, genioglossus, and geniohyoid muscles (answer b) are all superior to the hyoid bone and, therefore, superior to the thyroid gland. The superior, middle, and inferior pharyngeal constrictors (answer d) are all posterior or superior to the thyroid gland and thus would not be retracted. The trapezius, rhomboids, and levator scapula muscles (answer e) are all posterior to the neck and back and would not need to be retracted to gain access to the thyroid gland.

284. A 53-year-old woman has paralysis of the right side of her face that produces an expressionless and drooping appearance. She is unable to close her right eye, has difficulty chewing and drinking, perceives sounds as annoyingly intense in her right ear, and experiences some pain in her right external auditory meatus. Physical examination reveals loss of the blink reflex in the right eye on stimulation of either cornea and loss of taste from the anterior two-thirds of the tongue on the right. The inability to close the right eye is the result of involvement of which one of the following? a. Zygomatic branch of the facial nerve b. Buccal branch of the trigeminal nerve c. Levator palpebrae superioris muscle d. Superior tarsal muscle (of Müller) e. Orbital portion of the orbicularis oculi muscle

284. The answer is a. (Moore, pp 853-854.) The woman in the scenario has symptoms of Bell palsy. Palpebral portion of the orbicularis oculi muscle (innervated by the zygomatic branch of the facial nerve) produces the blink, whereas the orbital portion (answer e) is involved in "scrunching" the eye shut. In some individuals the temporal branch of the facial cranial nerve also innervates the upper portion of the orbicularis oculi muscle. The buccal branch of the facial nerve innervates muscles of facial expression (including the buccinator muscle and upper portion of orbicularis oris muscle) between the eye and the mouth, whereas the buccal branch of the trigeminal nerve (answer b) is sensory. The levator palpebrae superioris muscle (answer c), which elevates the upper eyelid, is innervated by the oculomotor nerve, whereas the involuntary superior tarsal muscle (answer d) is supplied by sympathetic nerves.

285. A 62-year-old rock musician falls out of a palm tree while vacationing in Fiji. He climbed the tree and fell while trying to reach one of the coconuts. He didn't think he had broken any bones in the fall. While he felt fine the day of the fall, the next morning he awoke with a bad headache and was relatively incoherent. At the Fiji ED, both frontal and lateral skull plain films show no evidence of any fracture, but during the physical examination papilledema is noted in both eyes. He is flown to New Zealand where head CT findings are consistent with which one of the following diagnoses? a. Epidural hematoma b. Subdural hematoma c. Pituitary tumor d. Graves disease e. Trigeminal neuralgia

285. The answer is b. (Moore, pp 876-877, 908.) The head CT findings were consistent with subdural hematoma. This is the most likely finding. Falls in older adults (while 62 many not be old for those young at heart) that do not produce skull fracture may still provide enough force to cause the brain to move in relationship to the meningeal layers causing bleeding inside the skull. (Older brains tend to shrink due to slow neuronal loss leaving more space for movement within the skull.) Subdural hematomas are often due to a tearing of cerebral veins as they enter the superior sagittal sinus. As the vein tears, it often bleeds into a potential space inside the dura mater, but outside the fluid-impervious outer layer of the arachnoid mater. Those are veins that bleed into this potential space, so bleeding is often slow to develop. Subdural hematomas are usually treated by drilling a small hole in the skull over the center of the hematoma and removing the blood clot. Normally the initial tear of the vein repairs itself with time. Epidural hematomas (answer a) are rare if there are no skull fractures. A pituitary tumor (answer c) might affect vision, but normally does not cause papilledema. Graves disease (answer d) may produce exophthalmus and would be present before the fall. Trigeminal neuralgias (answer e) are rarely produced by falls.

286. A 1-week-old neonate is brought to the pediatric office by her first time mother. The 8 lb 3 oz baby girl is alert, but arrives at the office in the detachable car seat with her head turned to the left while tilting her head toward the right as if she is trying to touch her right ear to her chest. The muscles on the left side of her neck are slightly stretched and the baby can move her head around a little bit, but not far from the tilted and turned position. This condition was not noticed at birth, and the new mother and baby left the hospital just 24 hours after the vaginal delivery. What muscle in the baby's neck was likely torn during the vaginal delivery and what is the name for the condition? a. Anterior scalene muscle, congenital muscular torticollis b. Sternocleidomastoid muscle, congenital muscular torticollis c. Sternocleidomastoid muscle, spasmodic torticollis d. Trapezius muscle, floppy head syndrome e. Trapezius muscle, spasmodic torticollis

286. The answer is b. (Moore, pp 1007, 1008.) The sternocleidomastoid muscle most likely became overstretched during the birthing process. As the muscle fibers start the process of repair, the remaining muscle fibers contract to limit head movement, a process called guarding. Generally physical therapy involving gently stretching the sternocleidomastoid muscle is effective at slowly reversing the condition. A modified cervical collar, called a tubular orthosis for torticollis is effective in aiding proper head positioning if the condition persists beyond 4 months of age. Spasmodic torticollis (answer c) is a sudden contraction of the sternocleidomastoid muscle and usually presents in adulthood. The anterior scalene muscle (answer a) connects from transverse cervical processes down to the superior surface of the first rib and would simply cause the neck to tilt to one side, with little or no head rotation. Tearing of the trapezius muscle (answers d and e) during birth is very rare and would cause the baby's head to tilt upward and to one side. Floppy (or dropped) head syndrome (answer d) is a condition that occurs in adults and may be associated with a variety of neuromuscular diseases including amyotrophic lateral sclerosis (ALS) also known as Lou Gehrig disease, Parkinson disease, myasthenia gravis, polymyositis, and genetic myopathies.

287. A 37-year-old mother delivers a full-term 7 lb, 10 oz baby boy. The baby boy has a left cleft of the upper lip that extends upward toward the left nostril and left anterior cleft of the primary palate just deep to the cleft lip. The mother has two other children without clefts at home. The obstetrician explains to the mother that these defects are most likely due to a failure of which one of the following embryonic processes? a. Mandibular process to fuse with the lateral nasal process b. Mandibular process to fuse with the medial nasal process c. Maxillary process to fuse with the lateral nasal process d. Maxillary process to fuse with the medial nasal process e. Lateral and medial nasal processes to fuse with each other

287. The answer is d. (Moore, pp 946, 949. Sadler, pp 284-285.) The lateral nasal process forms the alar region of the nose. Normally the maxillary process grows medially and fuses with the medial nasal process at the philtrum on both sides of the upper lip. The fact that the cleft involves both the lip and bony primary palate suggests failure of the maxillary process to fuse with the medial nasal process. The mandibular process (answers a and b) does not normally fuse with either the lateral or medial nasal processes (answer c). This would reduce the size of the mouth. The lateral and medial nasal processes (answer e) fuse to form a nostril separate from the oral cavity.

288. A 2-month-old infant is brought to a pediatric ophthalmology practice by her father. The baby girl almost always holds her head down with her chin resting on her chest. The father thinks that the baby's left eye has normal function and follows a bright and noisy rattle, however, the baby girl's right eye cannot follow any object held below the horizon of her normal gaze. When the ophthalmologist holds the baby's head gently in the normal anatomic position relative to her body and the rattle is held and shaken either medially or laterally above the girl's head both right and left eyes follow the rattle. However, the baby's right eye cannot follow the rattle when it goes below the horizon of her visual field. Which extraocular muscle does the ophthalmologist suggest be injected with botulinum toxin to potentially correct the baby's strabismus? a. Right inferior oblique muscle b. Right inferior rectus muscle c. Right lateral rectus muscle d. Right superior oblique muscle e. Right superior rectus muscle

288. The answer is e. (Moore, pp 898-903.) The baby's right eye is unable to be depressed below the horizon of normal gaze because of tonic contraction of the superior rectus muscle. Normally both the inferior rectus and superior oblique muscles help depress the eye and allow downward gaze. Botulinum toxin (Botox) inhibits acetylcholine release at the neuromuscular junction thus causing a flaccid paralysis of the muscle that is injected. The other extraocular muscles may then be able to function and permit downward gaze. If the right inferior oblique muscle (answer a) is injected, the eye would tend to migrate downward, but outward. If the right inferior rectus muscle (answer b) is injected with Botox, then the eye would tend to migrate further upward and medially. If the right lateral rectus muscle (answer c) is injected and becomes flaccid, then the eye would tend to gaze only medially. If the right superior oblique muscle (answer d) is injected with Botox, then the eye would tend to migrate upward and laterally.

289. A 9-year-old girl is brought to the pediatric office by her mother because the girl has been complaining about a very sore throat. The mother notes that her daughter has started to snore loudly at night. Examination of the girl's mouth and oropharynx reveals the likely source of the problem to be extremely large palatine tonsils. Surgical removal of the tonsils is the suggested treatment, but it is explained that there is a small risk associated with the surgery, which may result in which one of the following? a. Loss in the ability to taste salt on the anterior two-thirds of the tongue b. Loss in the ability to protrude her tongue, thus limiting her ability to lick an ice-cream cone c. Weakness in the ability to open her mouth fully when eating an apple due to damage to the innervation of the lateral pterygoid muscle d. Loss in the ability to taste on the posterior one-third of the tongue and perhaps some difficulty in swallowing e. Weakened ability to move her jaw from side-to-side because of loss in innervation of the medial pterygoid muscle

289. The answer is d. (Moore, p 1047.) The palatine tonsil sits in the lateral wall of the oropharynx in the palatine arch posterior to the palatoglossus muscle and anterior to the palatopharyngeus muscle. The glossopharyngeal CN (IX) traverses the bed of the palatine tonsil and carries afferent information to the brain regarding both general sensation and the special sense of taste from the posterior one-third of the tongue. The glossopharyngeal nerve is at risk for being cut during tonsillectomy. The ability to detect taste from the anterior two-thirds of the tongue (answer a) is not at risk because that information is carried by the lingual nerve, below the tongue. The ability to protrude the tongue (answer b) is provided by innervation from the hypoglossal nerve, which innervates all the intrinsic tongue muscles and lies below the tongue and is not a risk. The mandibular division of the trigeminal CN V (V3) does not course near the palatine arch and would not be at risk. It aids in the opening of the mouth (answer c) and movement of the mandible from side-to-side (answer e).

290. A 9-year-old boy is brought to the emergency department by his mother. He tripped on the carpet while playing tag with his sister in the living room and fell face-first onto the corner of a wooden coffee table. Fortunately, his eye just missed the corner of the table, however, his left cheek hit the table just below his eye forcing the lower lateral margin of the eye away from the orbit. Gentle palpation indicates that both his zygomatic bone and a lateral portion of the maxilla are broken and dislocated from the rest of his face. The boy's nose, medial portion of the maxillary bone and maxillary teeth are all intact. When the "H" test is performed, the left eye has more limited movement than the right eye and cannot look above the horizon. Which extraocular muscle is likely trapped in which facial bone? a. Inferior rectus muscle in the ethmoid bone b. Inferior rectus muscle in the maxillary bone c. Medial rectus muscle in the frontal bone d. Medial rectus muscle in the maxillary bone e. Superior rectus muscle in the sphenoid bone

290. The answer is b. (Moore, p 909.) Inferior rectus muscle was trapped in the maxillary bone. The breaking and dislocation of the zygomatic bone and part of the maxillary bone would be a modified type II Le Fort fracture, typical of a so-called "blowout" fracture. Since the left eye could not gaze above the horizon, the inferior rectus muscle was most likely trapped in the inferior orbital fissure, a site of weakness of the maxillary bone. The ethmoid bone (answer a) forms part of the medial wall of the orbit adjacent to the medial rectus muscle (answers c and d), both of which are uninvolved in this injury. The superior rectus muscle (answer e) elevates the eye allowing superior gaze. It runs along the frontal bone and is not affected in this scenario.

291. A 43-year-old mother of two watching her son play baseball is hit on the side of the head with a foul ball from another field. She is knocked unconscious for a few seconds and is taken to the ED of a local hospital by her husband. At the ED in addition to observing a growing "goose egg" over her right temporal region, examination of her fundi with an ophthalmoscope shows subtle papilledema. She is immediately sent for frontal and lateral skull films, which show a fracture in the frontal bone near the pterion. Head CT shows an accumulation of blood near the fracture under the frontal bone, but anterior to the coronal suture. What is the most likely working diagnosis provided to the on call neurosurgeon to bring her into the hospital on a Saturday afternoon? a. Extracranial hematoma b. Extracranial and epidural hematomas c. Extracranial and subdural hematomas d. Subarachnoid hemorrhage e. Extracranial hematoma and subarachnoid hemorrhage

291. The answer is b. (Moore, pp 876-877.) The most likely diagnosis is extracranial and epidural hematomas. The extracranial hematoma is the growing "goose egg" that was developing on the outside of her head. This condition is not life threatening. The physical findings of papilledema, frontal bone skull fracture, and accumulating blood inside the cranial bones anterior to the cranial suture are all consistent with epidural hematoma. Most likely the frontal bone fractured, lacerating the frontal branch of the middle meningeal artery and veins which run in grooves near the pterion. The temporal region of the skull is particularly thin in this region and more prone to compression fractures. Subdural hematomas (answer c) rarely present in a limited area, rather they occupy one complete cerebral hemisphere as the arachnoid mater separates from the dura mater. It is unlikely that a spinal tap, if performed would contain blood (indication of subarachnoid hemorrhage [answers d and e]).

292. A 23-year-old Caucasian man boxes semiprofessionally. He was once knocked out by a right "hook" to the head, and for about a week afterwards he had frequent headaches and a very runny nose, which finally stopped running by itself. However, he still remains unable to smell with his left nostril. What is the most likely site of injury that explains the symptoms? a. Fracture at the cribriform plate b. Fracture of the lacrimal bones c. Fracture of the nasal bones d. A Le Fort II fracture e. A Le Fort III fracture

292. The answer is a. (Moore, pp 1054-1058, 1078.) A fracture through the cribriform plate would likely cause both a leaking of cerebrospinal fluid (CSF) out of the nose (rhinorrhea) and headaches. It would likely shear off the olfactory nerves that pass through the cribriform plate of the ethmoid bone, resulting in left-sided anosmia (inability to smell). The lacrimal bone (answer b) surrounds the nasal lacrimal duct and if fractured might lead to a runny nose, but this would not explain the anosmia. The nasal bone (answer c) forms the root of the nose and is often broken in boxers, but such a fracture would not necessarily lead to a runny nose or continued headaches. Le Fort fractures (answers d and e) are fractures of the face involving the displacement of the maxillary and nasal region (type II) including displacement of the maxilla and zygomatic arch, thus displacing the maxillary teeth, nose, and zygomatic arch (type III). Neither of the Le Fort fractures would fit with the symptoms.

293. A 19-year-old undergraduate student arrives at the emergency department (ED) via ambulance. He was in a bicycle accident in which he flew over his handlebars and landed on the edge of the curb, striking the right side of his mandible. The ED physician determines that the mandible is broken by holding both sides of the mandible and feeling independent movement of the right and left sides. Not only has the teenager fractured his mandible, but his maxillary incisors have cut completely through his lower lip on the right side. While suturing the lower lip laceration it is noticed that the teenager has no sensation within his lower lip on the right side, while the left side of the lower lip has normal sensation. Based on the loss of sensation within the lower lip, what is the location of the fracture? a. Body of the mandible posterior to the mental foramen b. Coronoid process of the mandible c. Mandibular symphysis in the midline d. Neck of the mandible inferior to the condyle e. Ramus of the mandible superior to the mandibular foramen

293. The answer is a. (Moore, p 927.) The mandible is fractured posterior to the mental foramen, since the mental nerve is cut. The inferior alveolar nerve enters the ramus of the mandible at the mandibular foramen, then supplies all the mandibular teeth, but gives off the mental nerve that exits the mental foramen and innervates the lower lip. Thus, a fracture across the body of the mandible anterior to the angle and posterior to the mental foramen would likely sever the inferior alveolar nerve, resulting in the loss of sensation within the lower lip. A fracture at the coronoid process of the mandible (answer b) would only detach the temporalis muscle from its insertion onto the mandible. A fracture at the mandibular symphysis (answer c) would not affect lower lip sensation since there are no nerves that cross the midline. A fracture at the neck of the mandible (answer d) would only compromise blood supply to the head of the mandible, which usually does not undergo necrosis as a consequence of its small size. A fracture at the ramus of the mandible superior to the mandibular foramen (answer e) would not affect the inferior alveolar nerve.

294. A 17-year-old adolescent arrives at the ED with her jaw wide open and an apple core in her left hand. She is in obvious pain from dislocating her jaw, displacing the articular disk beyond the articular tubercle of the temporomandibular joint while eating the apple. The dislocation was the result of excessive contraction of which one of the following muscles? a. Buccinator b. Lateral pterygoid c. Medial pterygoid d. Masseter e. Temporalis

294. The answer is b. (Moore, pp 921-922, 927.) The temporalis, masseter, and medial and lateral pterygoid muscles are the muscles of mastication that attach to the mandible. The buccinator muscle (answer a), which controls the contents of the mouth during mastication, is innervated by the facial CN VII. The lateral pterygoid muscles, acting bilaterally, protract the jaw and, acting unilaterally, rotate the jaw during chewing. Because the fibers of the superior head of the lateral pterygoid muscle insert onto the anterior aspect of the articular disk of the temporomandibular joint as well as onto the head of the mandible, spasm of this muscle, such as in a yawn, can result in dislocation of the mandible by pulling the disk anterior to the articular tubercle. Reduction is accomplished by pushing the mandible downward and backward, so that the head of the mandible reenters the mandibular fossa. The temporalis (answer e), medial pterygoid (answer c), and masseter (answer d) muscles primarily elevate the jaw in molar occlusion.

295. A physician views the anterior neck of a 24-year-old male medical student. He has a reddish spot (in circle) that is in the center of a slightly raised area just anterior to his sternocleidomastoid muscle about one and a half inches superior to his jugular notch. This reddish raised area has existed for as long as he can remember. When the physician gently pushes on it, it feels attached to a structure that extends superiorly from this location. The patient reports that "at times it leaks a little clear fluid" after he has been heavily exercising for long periods of time. Which one of the following is the most likely congenital anomaly in this patient? a. Glossopharyngeal fistula b. An internal branchial sinus c. A branchial fistula d. A hyperactive sebaceous gland e. Spina bifida occulta f. Thyroglossal duct cyst

295. The answer is c. (Moore, p 1048-1049.) This congenital anomaly is a branchial fistula. When the pharyngeal pouches persist, they may form connections to the exterior of the neck immediately anterior to the boundary of the sternocleidomastoid muscle. Since this weeps fluid it is most likely a fistula or external cyst (not one of the options). An internal branchial sinus (answer b) would be a blind pouch off the pharynx and have no external connections. The internal opening for this fistula would most likely be within the bed of the palatine fossa (from the second pharyngeal pouch) or further inferiorly within the pharynx if it is from the third or lower pharyngeal pouches. Persistent glossopharyngeal fistula (answer a) (opening of the embryonic glossopharyngeal duct) more rarely makes a connection to the surface ectoderm and like a thyroglossal duct cyst (answer f) would be a midline structure. A hyperactive sebaceous gland (answer d) would not secrete a clear fluid. Spina bifida occulta (answer e) is associated with a tuft of hairy skin over a defect in the posterior arch of the spinal cord.

A 42-year-old woman is watching her son play baseball when a stray foul ball from another field unexpectedly strikes her in the back of the head and neck behind her left ear. A subcutaneous bulge rapidly appears, but she stays to watch the rest of the game and ices the bump when she arrives at home. The next day much of the swelling is diminished, but when she tries to eat an apple, or even when she swallows, it hurts deep behind her left ear. In addition, the patient reports the sensation of a foreign body in her throat and discomfort when turning her head. She travels to the urgent care clinic where the physician orders a lateral skull film that shows no fracture of her mastoid process. 296. The styloid process is fractured and displaced from the skull. To which one of the following bones is the styloid process attached? a. Ethmoid bone b. Mandible c. Occipital bone d. Sphenoid bone e. Temporal bone

296. The answer is e. (Moore, pp 826, 831.) The styloid process is attached to the temporal bone. The temporal bone has five major parts: the squamous, zygomatic, petrous, mastoid, and tympanic, in addition to the styloid process. The styloid process is not present in newborns, but grows as a bony projection from the temporal bone to serve as the site of attachment for two ligaments and three muscles. The ethmoid bone (answer a) lies superior to the nose. The occipital bone (answer c) forms the base of the skull around the foramen magnum and the caudal, posterior part of the skull. The sphenoid bone (answer d) constitutes a large part of the base of the skull more anteriorly and medially than the temporal bone.

A 42-year-old woman is watching her son play baseball when a stray foul ball from another field unexpectedly strikes her in the back of the head and neck behind her left ear. A subcutaneous bulge rapidly appears, but she stays to watch the rest of the game and ices the bump when she arrives at home. The next day much of the swelling is diminished, but when she tries to eat an apple, or even when she swallows, it hurts deep behind her left ear. In addition, the patient reports the sensation of a foreign body in her throat and discomfort when turning her head. She travels to the urgent care clinic where the physician orders a lateral skull film that shows no fracture of her mastoid process. 297. Which structure is most likely to cause tension on the styloid process when opening the jaw widely? a. Stylohyoid ligament b. Stylohyoid muscle c. Styloglossus muscle d. Stylomandibular ligament e. Stylopharyngeus muscle

297. The answer is d. (Moore, pp 919, 922, 923.) The stylomandibular ligament connects the styloid process to the inferior angle of the mandible along the posterior edge of the ramus. When the jaw is opened wide, especially when biting an apple or yawning, stress is placed on the ligament, causing pain. The stylohyoid ligament connects the styloid process to the lesser horn of the hyoid bone and generally limits the extent to which the hyoid bone and the larynx moves inferiorly. The larynx rises during swallowing, resulting in shortening of the stylohyoid ligament (answer a). Therefore, this is the least likely source of pain. The stylohyoid muscle (answer b) raises the hyoid bone and larynx during swallowing, but not when yawning. During yawning the larynx tends to move inferiorly, not superiorly. The styloglossus muscle (answer c) raises and retracts the base of the tongue during swallowing, but is not likely to be active during yawning. The stylopharyngeus muscle (answer e) helps raise the pharynx during swallowing, but is unlikely to specifically contract during yawning.

298. A 53-year-old banker develops paralysis on the right side of his face, which produces an expressionless and drooping appearance. He is unable to close the right eye and also has difficulty chewing and drinking. Examination shows loss of the blink reflex in the right eye to stimulation of either right or left cornea. Lacrimation appears normal on the right side, but salivation is diminished and taste is absent on the anterior right side of the tongue. There is no complaint of hyperacusis. Audition and balance appear to be normal. Where is the lesion located? a. In the brain and involves the nucleus of the facial nerve and superior salivatory nucleus b. Within the internal auditory meatus c. At the geniculate ganglion d. In the facial canal just distal to the genu of the facial nerve e. Just proximal to the stylomastoid foramen

298. The answer is d. (Moore, pp 861, 1081.) The patient has facial paralysis, which indicates injury to the facial nerve. A problem in the internal auditory meatus (answer b) usually affects hearing and balance. That the superior salivatory nucleus (answer a) is normal is indicated by normal lacrimation. Hence, the lesion must be distal to the origin of the greater superficial nerve at the genu of the facial nerve (answer c). However, absence of hyperacusis (inability to tolerate everyday sounds) indicates that the branch to the stapedius muscle is functioning normally, and suggests that the lesion is close to the stylomastoid foramen. Loss of taste and diminished salivation place the lesion proximal to the origin of the chorda tympani nerve. If the lesion were proximal to the stylomastoid foramen (answer e), taste and salivation would have been normal, with facial paralysis as the only sign.

300. An ENT is about to remove a pair of enlarged palatine tonsils from an 11-year-old boy who had chronic tonsillitis over the past 3 years. The palatine tonsils are located between the anterior and posterior palatine (faucial) pillars. The anterior and posterior palatine pillars are formed, respectively, by which of the following muscles? a. Levator veli palatini and tensor veli palatini b. Palatoglossus and palatopharyngeus c. Palatopharyngeus and salpingopharyngeus d. Styloglossus and stylopharyngeus e. Superior constrictor and middle constrictor

300. The answer is b. (Moore, pp 936-938.) The anterior palatoglossal arch, or anterior faucial pillar, is formed by the mucosa overlying the palatoglossal muscle. The posterior faucial pillar, or palatopharyngeal arch, likewise is formed by the palatopharyngeus muscle. The palatoglossus and palatopharyngeus muscles insert into the tongue and pharynx, respectively, and both are innervated by the pharyngeal branch of the vagus nerve (CN X). The tensor veli palatini and levator veli palatini, which arise from opposite sides of the auditory tube and base of the skull, insert into the soft palate. They are innervated, respectively, by the trigeminal nerve and the pharyngeal branch of the vagus nerve. The salpingopharyngeus muscle (answer c), also innervated by the pharyngeal branch of the vagus nerve, arises from the torus tubarius at the opening of the auditory tube and inserts into the pharyngeal musculature. The superior and middle pharyngeal constrictors (answer e) are innervated by the pharyngeal branch of the vagus nerve. The stylopharyngeus and styloglossus muscles (answer d) originate from the styloid process and insert onto the lesser horn of the hyoid and into the tongue, respectively. They are innervated by the glossopharyngeal and hypoglossal nerves, respectively. Levator veli palatini and tensor veli palatini muscles (answer a) are above the soft palate.

301. A 6 lb 14 oz baby girl was born to a 20-year-old mother. When the baby cried with her first few breaths the obstetrician noticed that the baby had a normal upper lip but a complete cleft of her hard and soft palate. The cleft prevents the baby from developing sufficient negative pressure for breast-feeding because of the continuity of the oral and nasal cavities. While bone and tissue can be pulled medially during surgery to repair the defect in the hard palate, separating the nose from the oral cavity, the most difficult part of the reconstruction is the repositioning of the muscles of the soft palate for proper function. Which perioral muscle aids in opening the Eustachian/auditory tube during each swallow to allow proper middle ear function and thus hearing? a. Masseter muscle b. Musculus uvulae muscle c. Palatoglossus muscle d. Palatopharyngeus muscle e. Tensor veli palatini muscle

301. The answer is e. (Moore, p 970.) The tensor veli palatini muscle has two functions: one to elevate the soft palate and second to open the Eustachian tube during each swallow (or yawn) to allow air to pass from the nasopharynx into the middle ear. The masseter (answer a) is a muscle of mastication that lies outside the oral cavity and raises the mandible during chewing and has nothing to do with soft palate function. The musculus uvulae muscle (answer b) raises the uvula. The palatoglossus muscle (answer c) forms the anterior edge of the palatine arch and helps lower the soft palate. The palatopharyngeus muscle (answer d) forms the posterior edge of the palatine arch and helps lower the soft palate and raises the pharynx during swallowing.

303. A patient is observed to suffer from hypoglossal hemiplegia. There is atrophy of the tongue on the right side and deviation of the protruded tongue to the right. In addition, the patient exhibits upper motoneuron paralysis on the left side of the body. Deviation of the tongue toward the right involves which one of the following? a. Left nucleus ambiguus b. Left pyramidal tract caudal to the decussation c. Right hypoglossal nerve d. Right nucleus ambiguus e. Right pyramidal tract rostral to the decussation

303. The answer is c. (Moore, p 1082.) Atrophy of the intrinsic musculature of the tongue on one side is due to a lesion of the ipsilateral hypoglossal nerve. Deviation of the tongue to the right on protrusion results from the unopposed action of the left genioglossus muscle, which is innervated by the left hypoglossal nerve. The hypoglossal nerve also innervates numerous other tongue muscles involved in deglutition. The question only asks about the cause of the tongue deviation so the other answers (answers a, b, d, and e) are not involved in controlling the tongue, rather CN X or limb functions.

304. A woman is found to have internal (medially directed) strabismus of the left eye, paralysis of the muscles of facial expression on the left side, hyperacusis of the left ear, and loss of taste from the anterior two-thirds of her tongue on the left. Her mouth is somewhat drier than normal. In addition, there is a lack of tearing in her left eye, and a blink reflex cannot be elicited from the stimulation of either the right or the left cornea. She has upper motor neuron paralysis of the right side of her body. Internal strabismus results from paralysis of which one of the following cranial nerves? a. Cranial nerve II b. Cranial nerve III c. Cranial nerve IV d. Cranial nerve V e. Cranial nerve VI

304. The answer is e. (Moore, pp 913, 1081.) The abducent nerve (CN VI) innervates the lateral rectus muscle. Remember, the "formula" LR6SO4. Lateral rectus is innervated by CN VI, superior oblique by CN IV, and the remainder of the extrinsic eye muscles by CN III. Loss of innervation to the lateral rectus results in unopposed tension by the medial rectus, which produces internal strabismus. The oculomotor nerve (CN III) innervates the medial, superior, and inferior recti, the inferior oblique, and the levator palpebrae superioris muscles. Paralysis of this nerve (answer b) would result in lateral deviation of the eye (external strabismus) accompanied by ptosis (drooping eyelid). In addition, mydriasis (dilated pupil) results from loss of function of the parasym-pathetic component of the oculomotor nerve. Damage to the trochlear nerve (CN IV) results in paralysis of the superior oblique muscle with impaired ability to direct the eye downward and outward (answer c). The optic nerve (answer a) is responsible for receiving the special sense of sight. The trigeminal cranial nerve (answer d) carries pain information from the eye.

305. During a neck dissection, the styloid process is used as a landmark. Which one of the following statements correctly pertains to one of the five structures that attach to the styloid process? a. The stylohyoid muscle attaches to the lesser horn of the hyoid bone. b. The styloglossus muscle acts to protrude the tongue. c. The stylohyoid ligament attaches to the lingula of the mandible. d. Distally the stylopharyngeus muscle is split by the digastric muscle. e. The stylomandibular ligament attaches to the lingula of the mandible.

305. The answer is a. (Moore, pp 984, 1002.) The stylohyoid muscle inserts onto the lesser horn of the hyoid bone (both derivatives of the second branchial arch) and raises that bone during swallowing. The distal tendon of the stylohyoid muscle is split by the digastric muscle (answer d) passing through its trochlea attached to the lesser horn. The styloglossus muscle acts to retract the tongue (answer b). The sphenomandibular ligament inserts onto the lingula of the mandibular foramen (answer c); the stylohyoid ligament inserts onto the lesser horn of the hyoid bone. The stylopharyngeus muscle inserts into the middle pharyngeal constrictor. The stylomandibular ligament (answer e) attaches to the posterior edge of the ramus of the mandible not to the lingula of the mandible.

306. A very concerned mother brings her teenager into their family practice office. The teenager awoke in the morning with a large swollen mass that filled part of his upper eyelid and medial forehead just above his left eye. His eyelid is so swollen he can barely keep it open. His history reveals indoor allergies and a persistent head cold. During the physical examination it is noted that purulent nasal discharge is present along with extreme tenderness to percussion over his paranasal sinuses. The large swollen mass in his eyelid and forehead is pliable. The physician prescribes intravenous antibiotics and provides which one of the following explanations to the very concerned mother and teenager? a. He suffers from trigeminal neuralgia that affects the ophthalmic portion of cranial nerve V. b. He suffers from tic douloureux that affects the ophthalmic portion of cranial nerve V. c. He suffers from sinusitis, which has eroded through the wall of the frontal sinus, and since the frontalis muscle is not attached to bone, allowed pus to leak into the upper eyelid. d. He has Bell palsy, which is generally caused by herpes simplex virus infection of the facial nerve within the facial canal that caused the loss of ability to raise the upper eyelid and thus allow fluid to accumulate within it. e. He suffers from a sty, which is an inflammation of meibomian or tarsal glands, which lie on the inner surface of the eyelid.

306. The answer is c. (Moore, pp 964-965.) He suffers from sinusitis, which has eroded through the wall of the frontal sinus, and since the frontalis muscle is not attached to bone, allows pus to leak into the upper eyelid. Inflammation of the mucous membrane that lines the sinuses may sometimes lead to a buildup of pus that can block the normal drainage pathways. If pressure builds, erosion of the bony wall of the sinus can occur. In this instance, the anterior wall of the frontal sinus was compromised and pus escaped into the forehead and into the upper eyelid, since the frontalis muscle, a normal barrier, attaches only into skin of the forehead. In order to allow movement, the skin of the eyelid is only attached to underlying structures by loose areolar connective tissue, through which infections easily spread. Intravenous antibiotics were initiated. The swelling spontaneously reduced after the first week of treatment and no visible defects were noted 1 month later. Trigeminal neuralgia or tic douloureux (answers a and b) is characterized by sudden sharp pains over the distribution of one or more branches of the trigeminal nerve. Although pain is perceived within the ophthalmic division, the teenager would not suffer from sudden sharp twinges of pain, rather a dull constant pain from swollen tissue. Bell palsy (answer d) is generally caused by a herpes simplex virus infection of the facial nerve within the facial canal. The resulting unilateral facial paralysis limits one's ability to close the upper eyelid, not raise it. A sty (answer e) is an inflammation of the sebaceous gland, associated with each eyelash or cilia. A chalazion is an inflammation of a meibomian or tarsal gland, which lies on the inner surface of the eyelid. This could cause a bulge in the upper eyelid, but does not fit with the other clinical findings.

307. During a prenatal ultrasound, images suggest that the fetus has a defective lower thoracic spinal cord. α-fetoprotein levels are two standard deviations above normal. It is suggested to the mother that the child be delivered via a Cesarean section to reduce the chances of damaging any protruding spinal cord and meninges. After birth, an ultrasound study determines that the covering of the spinal cord, along with the intact spinal cord, forms a saclike projection through a dorsal defect in the vertebral column. What is the proper term for this congenital condition? a. Rachischisis b. Anencephaly c. Meningocele d. Meningomyelocele e. Hydrocephaly

307. The answer is d. (Moore, p 463. Sadler, pp 302-303.) In the family of conditions known as spina bifida, failure of the dorsal portions of the developing vertebrae may expose a portion of the spinal cord and its covering. This usually occurs near the caudal end of the neural tube, often in the lumbar region. If there is no projection of the spinal cord or its covering through the bony defect, the condition is "hidden" (spina bifida occulta). However, the term spina bifida cystica is used when the spinal meninges are displaced from the spinal canal and into the defect. In a meningocele (answer c), there is a saclike projection formed only by the meninges. If the projection contains neural material, it is a meningomyelocele, which is the case for this newborn. Most newborns with lumbar meningomyelocele have loss of function of lower extremities and may also have bowel and bladder dysfunction because the spinal cord does not make proper neural connections as a result of its growing outside the normal spinal canal. Rachischisis, also known as myeloschisis (answer a), is an extreme example of spina bifida cystica in which the neural folds underlying the vertebral defect fail to fuse, leaving an exposed neural plate. Anencephaly (answer b) occurs when the cranial neural tube fails to fuse, thus resulting in lack of formation of forebrain structures and a portion of the enclosing cranium. Hydrocephaly (answer e) results from blockage of the narrow passageways between the ventricles or between the ventricles and the subarachnoid space. Resultant swelling of the ventricles compresses the brain against the cranial vault and may cause serious mental deficits.

308. A teenage baseball player is hit in the base of the skull by a thrown bat. He is hoarse and complains of difficulty swallowing. The cranial x-ray indicates a basal skull fracture that passes through the jugular foramen. The examining physician notes a large hematoma behind the ear on the injured side. If the nerves passing through the jugular foramen are severed as a result of the cranial fracture, which one of the following muscles will remain functional? a. Palatoglossus muscle b. Sternocleidomastoid muscle c. Styloglossus muscle d. Stylopharyngeus muscle e. Trapezius muscle

308. The answer is c. (Moore, pp 1009, 1082.) Cranial nerves IX, X, and XI pass out of the skull at the jugular foramen. The styloglossus muscle is innervated by the hypoglossal nerve, which leaves the posterior cranial fossa by way of the anterior condylar canal. In addition to the internal jugular vein, the jugular foramen contains the glossopharyngeal nerve (innervating the stylopharyngeus muscle [answer d]), the vagus nerve (innervating palatal [answer a], pharyngeal, and laryngeal musculature), and the spinal accessory nerve innervating the sternocleidomastoid (answer b) and trapezius muscles (answer e).

309. A tall, skinny, 14-year-old teenage boy is brought into the family practice office by his mother. She noticed that he snores loudly at night. When questioned, the teenager admits to having a sore throat ever since the family's new golden retriever started sleeping in his room several months ago. The boy failed to tell his mother about the sore throat because he always wanted a pet. When the physician examines the teenager, she notices enlarged submandibular lymph nodes. When the teenager opens his mouth, the potential cause of the problem is visible superior and lateral to the posterior of his tongue. What is the most likely cause of nighttime snoring in this teenager? a. A short uvula b. Eruption of wisdom teeth prematurely c. Enlarged lingual tonsils d. Enlarged palatine tonsils e. Mandibular tori f. The tongue stud he had gotten without his mother's noticing

309. The answer is c. (Moore, p 949. Fauci, p 1666.) Removal of enlarged palatine tonsils will often reduce snoring especially in children and teenagers, though less frequently than in adults. The enlarged pharyngeal tonsils or adenoids may also cause snoring, but they are located in the posterior of the nasopharynx. Obesity is a leading cause of snoring in adults, but this teenager was described as skinny. An enlarged or infected uvula may cause snoring, so a short uvula (answer a) is very unlikely to cause snoring. Premature eruption of the wisdom teeth (answer b) rarely causes snoring, but may cause impaction or crowding of existing teeth. Lingual tonsils (answer c) are found in the tongue and do not cause snoring. Mandibular tori are benign bony protrusions of the mandible toward the oral cavity that are covered with oral mucosa. Unless the mandibular tori (answer e) grow extremely large, they are unlikely to cause snoring. While the piercing of the tongue in order to place the tongue stud (answer f) produces swelling of the tongue that normally goes away by 7 to 10 days, a tongue stud is unlikely to cause snoring. In most states a minor would need parental permission for getting his tongue pierced.

310. Muscle relaxants are used routinely during anesthesia with resultant closure of the vocal folds. Laryngeal intubation by the anesthesiologist is necessary because which one of the following muscle(s) is/are unable to keep the glottis open? a. Cricothyroid muscles b. Lateral cricoarytenoid muscles c. Posterior cricoarytenoid muscles d. Thyroarytenoid muscle e. Transverse arytenoid muscles

310. The answer is c. (Moore, pp 1045-1046.) The posterior cricoarytenoid muscles rotate the arytenoids laterally, which swings the vocal process of that cartilage outward to abduct the vocal cords and open the glottis. These are the sole abductors of the vocal folds. The lateral cricoarytenoid muscles (answer b) and the unpaired transverse arytenoid muscle (answer e) adduct the vocal folds. The thyroarytenoid muscle (answer d) and its innermost portion, the vocalis muscle, act to tense the cords. The cricothyroid muscle (answer a) lengthens the vocal cords.

313. A 32-year-old woman was brought into the ED from a car accident. She was conscious, but had been knocked unconscious for a couple of minutes by the force of a car that had run a stop sign, broad-siding her vehicle. She has a hematoma over the parietal bone on the left side of her head. She complains of a stiff neck and tilts her head slightly to the right. While performing a cranial nerve examination, it is noted that her left eye has difficulty moving inferiorly from a fully adducted horizontal position, when she looks down at her feet. A head CT is ordered with specific imaging of which one of the following cranial nerves? a. Right cranial nerve III b. Left cranial nerve III c. Right cranial nerve IV d. Left cranial nerve IV e. Left cranial nerve VI

313. The answer is d. (Moore, pp 902, 1080-1081.) Cranial nerve IV has a long intracranial course, so it has an increased chance of injury. The nerve originates from the trochlear nucleus in the midbrain and is the only cranial nerve to exit the brain on the dorsal rather than ventral surface. It exits the middle cranial fossa by exiting the superior orbital fissure (along with CN III, V1, and VI). The nerve also does not pass through the common tendinous ring to reach the superior oblique muscle; CN IV is the only extraocular muscle to pass through a pulley, the trochlea. A patient with a cut CN IV tends to tilt her/his head toward the unaffected side (in this case to the right, thus not [answer c]). A physician examines individual extraocular muscle function by performing the "H" test (see High Yield Facts, Figure 17). To test the function of the superior oblique muscle (innervated by the trochlear nerve) the patient first looks medially (adduction) and then inferiorly (toward the nose). Cranial nerve III (answers a and b) is involved with the bulk of the other extraocular eye movements and is normal. Cranial nerve VI (answer e) innervates the lateral rectus muscle, which is responsible for abducting each eye, and is normal in this patient.

314. A 58-year-old man presents to the ENT clinic with complaints of headaches and nasal drainage. He has seasonal allergies, but this year he complains of headaches along with his allergies. The headache often feels as if it is between his eyes or "on top of his head." Upon examination of his nose and mouth, a large nasal polyp is seen on the medial aspect of the superior turbinate of his left nostril. A CT confirms a large nasal polyp in the left sphenoethmoid recess and sinusitis within an adjacent sinus. The sinusitis is most likely causing the headaches within which one of the following locations? a. Anterior ethmoid sinuses b. Frontal sinus c. Middle ethmoid sinuses d. Maxillary sinus e. Sphenoid sinus

314. The answer is e. (Moore, 956-958.) A nasal polyp within the sphenoethmoid recess is very likely to inhibit proper drainage of the sphenoid sinus increasing the likelihood of sphenoid sinusitis. While pain from sphenoid sinusitis can be described as behind or between the eyes, classically it refers pain to the vertex of the head. Sinusitis is a common cause of headaches. Pain for sinusitis within the anterior ethmoid sinuses (answer a) generally occurs between the eyes and the anterior ethmoid sinuses drain under the middle turbinate. Pain from sinusitis within the frontal sinus (answer b) presents as pain directly superficial to the frontal bone between the eyes within the glabellar regions. The frontal sinus drains inferior to the middle turbinate. Pain from sinusitis within the middle ethmoid sinuses (answer c) normally presents as pain between the eyes. The middle ethmoid sinuses drain inferior to the middle turbinate. Pain from sinusitis within the maxillary sinus (answer d) presents as pain within or cranial to the maxillary teeth. The maxillary sinus drains inferior to the middle turbinate.

315. The parents of a 3-year-old are upset because he has had six middle ear infections, forcing them to miss many days of work in order to stay home with the boy rather than send him to daycare. Most likely the boy's Eustachian (auditory) tube is not functioning correctly. In order to treat recurrent middle-ear infections, pressure-equalization (PE) tubes (or tympanostomy tubes) may be placed at what location within the tympanic membrane? a. At the umbo of the tympanic membrane b. At the attachment of the manubrium with the tympanic membrane c. At the pars flaccida of the tympanic membrane where the fibrous layer is missing d. In the inferior half of the tympanic membrane e. In the eustachian tube to keep it open, because that is often the cause of the initial problem

315. The answer is d. (Moore, pp 978-979.) PE or tympanostomy tubes that look like little plastic bobbins are typically positioned by cutting the inferior posterior portion of the tympanic membrane in a radial fashion. The umbo (answer a) is where the tip of the manubrium of the malleus is attached to the tympanic membrane (answer b) and would not be a site of insertion of a PE tube; thus both answers a and b are wrong. The pars flaccida (answer c) of the tympanic membrane is near the course of the chorda tympani nerve which is therefore a dangerous location for incisions to place tubes. It would be difficult to place a tube within the Eustachian tube (answer e), even though that is the site of the malfunction. PE tubes typically are pushed out of the tympanic membrane as the stratified squamous epithelium continually sloughs off cells at its surface, pushing on the external flang, and thus naturally popping the bobbin-like tube out of the membrane months later.

316. A 72-year-old grandmother is watching her grandson play baseball on one field, when a foul ball from another baseball diamond strikes the right side of her face, knocking her unconscious. She regains consciousness in the ambulance on the way to the hospital. Skull films reveal fractures of both her right zygomatic arch and the coronoid process on the right side of the mandible. Which two of the following muscles either originate from or insert onto the fractured structures, thus weakening the woman's ability to chew? a. Medial and lateral pterygoid b. Masseter and lateral pterygoid c. Masseter and medial pterygoid d. Stylohyoid and posterior belly of the digastric e. Temporalis and masseter

316. The answer is e. (Moore, pp 921-923.) The temporalis muscle elevates the mandible by inserting onto the coronoid process of the ramus of the mandible. The masseter muscle elevates the mandible by originating from the zygomatic arch and inserting on the outer angle of the mandible. The medial and lateral pterygoid muscles (answer a, b, and c) originate from the medial and lateral pterygoid plates which lie medial to the ramus and angle of the mandible and are not fractured in this vignette. The stylohyoid and posterior belly of the digastric (answer d) originate from the styloid process and mastoid process, respectively, and neither of those bones are fractured. Contraction of the temporalis, masseter, and medial pterygoid muscles helps elevate the mandible. The lateral pterygoid, stylohyoid, and posterior belly of the digastric muscles help lower or open the mandible.

317. A 63-year-old man is on the hospital service for workup of a stiff neck, the "worst headache" of his life, and general malaise. Two days earlier, he had a spinal tap, which was bloodless and consistent with viral meningitis. This morning the patient needs to turn his whole head when he looks at the nurse as she enters his hospital room. While his headache is improving, both his eyes have reduced ability to move laterally; rather he tends to turn his head. Ophthalmoscopic visualization of his fundi shows no evidence of papilledema. The site of his spinal tap is oozing some fluid. The rest of the cranial nerve examination is normal. Which one of the following is the most likely cause of his reduced eye movement? a. Viral meningitis b. Stretching of cranial nerve VI c. Excess cerebral spinal fluid that is stretching just cranial nerves III d. Bilateral tumors at the superior orbital fissures e. Normal stiffening process following hospitalization for couple of days

317. The answer is b. (Moore, pp 505-506, 1081.) A head CT is ordered with specific imaging of cranial nerve VI. One of the possible consequences of a spinal tap is continued leakage of cerebral spinal fluid (cerebrospinal fluid, CSF) at the site of the tap since the meninges have been compromised. If CSF continues to leak then autologous blood is injected at the site of the spinal tap to stimulate closing of the hole in the meninges. Sliding of the brain toward the foramen magnum occurs as a rare consequence of spinal taps. Since cranial nerve VI exits the brain at the junction of the medulla and the pons and then enters the Dorello dural cave along the clivus, it cannot slide down with the brain and thus would be subject to stretching. Stretching of the abducent nerve would likely lead to bilateral compromised ability to look laterally since no other cranial nerves can cause abduction of the eyes. Viral meningitis (answer a) would not cause a selective loss of both abducent cranial nerves. Excess CSF causes CN VI palsy, but generally not CN III palsy (answer c). Bilateral tumors at the superior orbital fissures (answer d) are unlikely, and also would compromise other cranial nerves as well. Loss of the ability to look laterally is not part of a normal course of hospitalization (answer e).

318. An 87-year-old man is having difficulty swallowing and often chokes on his food. You check his gag reflex by touching the posterior one-third of his tongue and palatine tonsil area. Which one of the following cranial nerves provides the afferent limb of the gag reflex? a. Cranial nerve I b. Cranial nerve II c. Cranial nerve III d. Cranial nerve IV e. Cranial nerve V f. Cranial nerve VI g. Cranial nerve VII h. Cranial nerve VIII i. Cranial nerve IX j. Cranial nerve X k. Cranial nerve XI l. Cranial nerve XII

318. The answer is i. (Moore, pp 949, 1082.) The cranial nerve that provides the afferent limb of the gag reflex is the glossopharyngeal, IX cranial nerve (answers a→h and j→l). Cranial nerve IX provides general sensation from the posterior one-third of the tongue and palatine tonsil area. The response to touching this area is to contract the soft palate and pharynx in a protective manor or gag reflex. The motor aspects of this reflex are mainly mediated by the vagus, cranial nerve X.

323. A physician witnesses a choking incident in a restaurant. The Heimlich maneuver is unsuccessful at removing the food from the pharynx. The victim is having extreme difficulty breathing and starts to pass out. Where is the best location to produce an emergency airway? a. In the midline just superior to the hyoid bone b. In the midline just inferior to the hyoid bone c. At the laryngeal notch d. At the junction between the thyroid cartilage and cricoid cartilage e. At tracheal ring 2 to 3 below the cricoid cartilage

323. The answer is d. (Moore, pp 1044-1045.) The food is most likely stuck in the laryngeal pharynx, so you must produce an alternative airway (called a tracheostomy) below the glottis, which reflexly closes. Locations around the hyoid bone (answers a and b) and above the laryngeal notch (answer c) are above the blockage and would not get air into the lungs. The isthmus of the thyroid gland generally lies in front of the second and third tracheal ring (answer e), and because it is so highly vascular, it is not an ideal location for an emergency airway. An additional alternative location for an emergency airway would be the jugular notch, but is not preferred because of the occurrence of a thyroid ima artery below the isthmus, in a small percentage of the population.

319. A 93-year-old nursing home patient is seen during morning rounds. She is quite upset because she awoke with double vision and an inability to open her left eye completely. Her physician performs a complete cranial nerve examination. Her left eye, under her drooping eyelid, is dilated and rotated down and outward. It lacks the normal pupillary reflex. There is no evidence of papilledema in either eye. The rest of the cranial nerve examination is normal. Which one of the following is the most likely explanation for this condition? a. An aneurysm of the left posterior cerebral artery compressing cranial nerve III b. An aneurysm of the right anterior cerebral artery compressing cranial nerve III c. A tumor at the left optic canal d. Glaucoma e. A left parotid gland tumor compressing cranial nerve VII

319. The answer is a. (Moore, pp 913, 1080.) This condition is most likely due to an aneurysm of the left posterior cerebral artery compressing cranial nerve III. The woman's symptoms, ptosis of the upper eyelid, an eye that is rotated downward (because superior oblique muscle, innervated by CN IV is still functioning functional) and outward (because the lateral rectus muscle, innervated by CN VI is still functioning) with a dilated pupil (because sympathetics, which innervate the dilator pupil muscles are still functional) are all consistent with loss of function of cranial nerve III. An aneurysm in either the posterior cerebral or superior cerebellar artery often compresses cranial nerve III as it exits the midbrain. An aneurysm of the right anterior cerebral artery (answer b) would be very unlikely to cause a problem for the left third cranial nerve. A tumor within the left optic canal (answer c) would affect the left optic nerve which passes through it. Cranial nerve III passes into the orbit through the superior orbital fissure along with CN IV, V1, and VI. Neither glaucoma (answer d) nor a parotid gland tumor (answer e) would present with those symptoms.

320. A 73-year-old man presents because of repeated biting of his tongue and cheek, and difficulty chewing. The left side of his tongue is somewhat swollen and he has two different cuts on it. His left cheek is slightly less full over the angle of the mandible compared to the right side. He has very little sensation over his left mandible, along the side of his head, and on the left side of his tongue. He has weakened ability to elevate his mandible on the left side. Taste sensation on his tongue is normal. He also complains of slight dryness on the left side of his mouth. The rest of his cranial nerve examination is normal. A head CT is ordered because his physician suspects which one of the following? a. A tumor at the left superior orbital fissure b. A tumor blocking the left foramen rotundum c. A tumor blocking left foramen ovale d. A tumor blocking the left internal acoustic meatus e. A tumor blocking the right internal acoustic meatus

320. Answer is c. (Moore, pp 1065-1067.) It is suspected that a tumor is blocking the left foramen ovale. The mandibular division of the trigeminal cranial nerve exits the skull through the foramen ovale. This division provides general sensation to the tongue (via the lingual nerve) and mandibular teeth (via the inferior alveolar nerve) and area over the mandible (via the buccal nerve). In addition, the mandibular division of the trigeminal also innervates eight muscles (the four muscles of mastication [temporalis, masseter, medial, and lateral pterygoid muscles], two associated with the floor of the mouth [the mylohyoid and anterior belly of the digastric muscles], and two tensors [tensor tympani in the middle ear and tensor veli palatini in the soft palate]). In addition, preganglionic nerves from cranial nerve IX (via the lesser petrosal nerve) also pass through the foramen ovale on their way to stimulate the parotid salivary gland. A tumor at the superior orbital fissure (answer a) would affect eye movements and forehead sensation. A tumor at the foramen rotundum (answer b) would affect sensation under the eye on the face and maxillary teeth pain. A tumor at the internal acoustic meatus (answers d and e) would affect the facial nerve, hearing, and balance.

321. A 43-year-old man presents with left-sided maxillary tooth pain of one week's duration. Because he thought it might have been one of his maxillary fillings (the newer plastic polymers) he visited his dentist first, but his dentist was unable to identify any dental problems. His physician taps on his maxillae and elicits sharp pain when she taps on the left, but not right side of his face. While he does not think he has any allergies, he admits that his girlfriend has recently bought a cat that lives inside. A sinus series is ordered because his physician suspects which one of the following? a. Sphenoid sinusitis b. Anterior ethmoidal sinusitis c. Posterior ethmoidal sinusitis d. Maxillary sinusitis e. Frontal sinusitis

321. The answer is d. (Moore, p 964.) A sinus series is ordered because his physician suspects that he has maxillary sinusitis. The maxillary sinus is the most frequent site of sinusitis. This is likely due to the fact that its ostium is high on the medial wall of the sinus, thus requiring ciliary action to drain the sinus when in the anatomical position. Lying on his right side may help this patient drain his left maxillary sinus. The maxillary sinus ostium is generally large enough that a cannula can be threaded into the sinus and vacuum applied to help drain it. Sphenoid sinus pain (answer a) is generally referred to the top of the skull near the vertex. Anterior (answer b) and posterior (answer c) ethmoidal sinus pain refers to areas around the eyes (either medial or lateral). Frontal sinusitis pain (answer e) presents over the frontal sinus and tapping on the forehead there will elicit pain.

322. Access to the heart is typically obtained by placing venous catheters. While at times the cephalic vein is used, other times a location closer to the heart is desired. It is essential to access a low-pressure central vein, rather than a high-pressure central artery. When performing a cardiac catheterization of the right heart chambers it is important for the cardiologist to remember that the carotid sheath contains which of the following? a. Internal carotid artery (lateral), internal jugular vein (medial), and sympathetic chain b. Internal carotid artery (medial), external jugular vein (lateral), and sympathetic chain c. Internal carotid artery (medial), external jugular vein (lateral), and phrenic nerve d. Internal carotid artery (lateral), internal jugular vein (medial), and phrenic nerve e. Internal carotid artery (medial), internal jugular vein (lateral), and the vagus nerve

322. The answer is e. (Moore, pp 999-1000, 1011.) The correct answer is the internal carotid artery (medial), internal jugular vein (lateral), and the vagus nerve. Answers a and b are not correct because the carotid sheath contains the vagus, not the sympathetic chain, nor the phrenic nerve (answers c and d). The internal carotid artery (which has a palpable pulse) is medial and the internal jugular vein, into which the cardiac catheter is inserted, has a lateral location within the carotid sheath.

325. A 68-year-old woman presents to the ENT clinic because of a small lump on the right side of her face just anterior to her ear. At first it is thought to be an enlarged lymph node, but careful examination of her ear and scalp fails to confirm the diagnosis. The small lump appears to be within the superficial portion of the parotid salivary gland, anterior to the external ear and posterior to the masseter muscle. A needle biopsy of the lump is performed and sent for pathological assessment. The diagnosis is a pleomorphic adenoma of the parotid gland. The tumor needs to be surgically removed. Which one of the following is a serious potential risk of the surgical resection procedure? a. Loss of her ability to taste on the right side of her tongue b. Loss of her ability to chew on the right side of her mouth c. Right-sided facial muscle paralysis d. Loss of her ability to move the right side of her tongue e. Increased sensitivity to sounds on the right side

325. The answer is c. (Moore, pp 926, 1081.) One of the risks of the surgical resection is that she may develop right-sided facial muscle paralysis. About 80% of salivary gland tumors originate from within the parotid salivary gland. The facial nerve sends out motoneurons from the stylomastoid foramen. That nerve then branches into 5 to 7 major branches that innervate the muscles of facial expression (derived from the second branchial arch). The branches divide while passing through the substance of the parotid salivary gland. The branches are named for the anatomic regions that they serve: temporal; zygomatic; buccal; mandibular; cervical; and posterior auricular branches. While it is unlikely that all of those branches would be cut while removing the parotid tumor, they all are potentially at risk. The tumor is described as superficial within the parotid gland and since the facial nerve normally passes through the middle of the gland, the facial nerve might be spared. The patient in the vignette is very unlikely to lose the sense of taste (answer a). That information is carried in the lingual and chorda tympani nerves, which are much deeper and unlikely to be at risk. The mandibular division of the mandible innervates the muscles of mastication and exits the skull at the foramen ovale deep to the parotid and protected by the lateral pterygoid muscles, so losing the ability to chew on the right side is unlikely (answer b). The hypoglossal nerve innervates tongue muscle (answer d) from below the tongue, so is not in jeopardy of being cut. The tensor tympani receives innervation from the mandibular division of the trigeminal nerve as it exits the foramen ovale which is deep to the surgical area, thus not in danger (answer e).

326. A 53-year-old woman presents with hearing loss and ringing in her left ear. About a month ago she experienced dizziness and felt sick, but that seemed to pass. She describes recent and numerous headaches, always on the left side. A complete cranial nerve examination is completed. Everything is normal except for the hearing loss and weakness in her left facial muscles. A head MRI is ordered because of concerns about which one of the following? a. Conductive hearing loss b. Ménière disease c. Acoustic neuroma d. Tic douloureux e. Parotid gland tumor

326. The answer is c. (Moore, p 1082.) An acoustic neuroma is a benign tumor of the Schwann cells that myelinate the vestibular portion of the VIII cranial nerve. Even though the tumor arises on the vestibular portion of the VIII cranial nerve, hearing loss (answer a) is usually the first reported symptom. Tinnitus or ringing in the ear and headaches are also frequently reported. While the vestibular system may be disrupted (this patient complained of dizziness) the vestibular system on the right side is functioning normally and provides enough information once the individual becomes accustomed to the loss. In this case the tumor has started to affect the VII cranial nerve which controls the muscles of facial expression. Her symptoms go beyond conductive hearing loss (she is also young [53] to be suffering from conductive hearing loss). Ménière disease (answer b) is an excess accumulation of endolymph, which is usually associated with hearing loss, tinnitus, and vertigo (all reported in this woman), but would not be associated with any facial paralysis. Tic douloureux (or trigeminal neuralgia; answer d) is characterized by sudden pain along the distribution of the trigeminal nerve and is not a presenting problem. A parotid gland tumor (answer e) could result in the loss of control of the muscles of facial expression, but hearing and balance would generally be unaffected.

328. A 19-year-old man presents in extreme pain holding a handkerchief over his right eye. He explains that he was accidentally struck in the eye with a pool cue and the he can't see anything other than a milky white cloud in his right eye. On examination of his right eye, there appears to be a scratch on the cornea, the anterior chamber of the eye is partially filled with blood, but the eye has not ruptured. Intraocular pressure as measured with a tonometer is normal. The patient is told that it is important to avoid any other blows to the head since the retina is at increased risk for detachment and to return to the office the next day to determine if the intraocular pressure has risen. There are abnormal red blood cells in the aqueous humor that may plug the normal site of drainage, leading to excessive intraocular pressure if left untreated. Where in the anterior chamber of the eye does aqueous humor normally drain? a. Trabecular meshwork that leads to the scleral venous sinus (canal of Schlemm) b. Ciliary muscle which has zonular fibers (suspensory ligament of the lens) attached to it c. Ciliary process d. Lens e. Retina

328. The answers is a. (Moore, pp 907, 912.) Aqueous humor is produced by the ciliary processes which project from the ciliary body (answer c), in the posterior chamber. Aqueous humor flows through the pupil into the anterior chamber, where it normally drains through the trabecular mesh-work that leads to the scleral venous sinus (canal of Schlemm, see Question 267 and feedback). This trabecular meshwork can become plugged with red blood cells, especially if some blood clotting occurs. If the trabecular meshwork is blocked, then intraocular pressure builds up in the eye, which if excessive, can lead to blindness. This is the reason for daily intraocular pressure monitoring until the blood clears. When intraocular pressure increases suddenly (hours) it is very painful, and the pressure must be relieved by inserting a small needle at the corner of the cornea and applying pressure elsewhere, thus releasing fluid in a procedure called "burping the eye." As the intraocular pressure is normalized, the eye pain subsides. Gradual increases in intraocular pressure, however, may go undetected because they are not always painful (such as in the case of glaucoma). The ciliary muscle which has zonular fibers (suspensory ligament of the lens) attached to it (answer b) controls the shape of the lens, but does not drain aqueous humor. It also lies in the posterior not the anterior chamber of the eye. The lens (answer d) is not the site of drainage of aqueous humor and is located in the posterior chamber of the eye. The retina (answer e) is not the site of drainage of aqueous humor and is located in the posterior four-fifths of the eye surrounding the vitreous body (humor) of the eye (Also see Question 267 and feedback).