Grey's Anatomy - Practice Questions

A 79-year-old male retired military veteran presents to the outpatient clinic with an abnormal curvature of the vertebral column. He complains that it has become increasingly painful to walk around town. Upon physical examination he has an abnormally in creased thoracic curvature resulting from osteoporosis. Which of the following is the most likely clinical condition of this patient's spine? 0 A. Scoliosis 0 B. Kyphosis 0 C. Spinal stenosis 0 D. Lordosis 0 E. Herniated disk

16 B. Scoliosis is de fin ed as a lateral deviation of the spinal column to either side. Kyphosis is an in creased prima ry curvature of the spinal column. This curvature is associated with thoracic and sac ral re gions and is most likely this patient's clinical condi- tion. Spinal stenosis is a narrowing of the vertebral canal and is not directly associated with a displace ment of the spi nal column. Lordosis is the increased secondary curvature affecting the cervical and lumbar regions. A herniated disk is a rupture of the anulus fibrosus of the inte rvertebra l d isk, commonly causing a posterolate ral displacement of the nucleus pulpos us into the vertebral canal.

A 3-year-old child is admitted to the emergency department with evere headache, high fever, mal ai e and confusion. Radiographic and physical ex aminations reveal that the patient suffers from men ingitis. A lumbar puncture is ordered. Which vertebral level is the most appropriate location for the lumbar puncture? 0 A. T12-L1 0 B. L1-2 0 C. L2-3 0 D. L4-5 0 E. L5-S1

6 D. A lumbar puncture is performed by taking a sample of CSF from the lumbar cistern (the subarach noid space below the spinal cord) between vertebrae L4 and LS or sometimes between L3 and L4. It is done in this region because the spinal cord ends at the level of L1 to 12 and the dural sac ends at the level of S2. Therefore it is the safest place to do the procedure because it lies between these areas and the risk of injuring the spinal cord is avoided.

A 19-year-old man is brought to the emergency department after dislocating his shoulder while playing football. Following treatment of the dislocation, he can not initiate abduction of his arm. An MRI of the shoul der shows a torn muscle. Which muscle was most likely damaged by the injury? 0 A. Coracobrachialis 0 B. Long head of the triceps 0 C. Pectoralis minor 0 D. Supraspinatus 0 E. Teres major

6 D. The rotator cuff muscles are common sites of damage dw-ing shoulder injuries. These muscles in clude the supraspinatus, infraspinatus, teres minor, and subscapularis (SITS). Initiation of abduction of the humerus (the first 15°) is performed by the supra spinatus, followed by the deltoid from 15° to 90°. Above the horizontal , the humerus is abducted by the trapezius and serratus anterior. The teres major and the pectoralis major are responsible for medial rota tion and adduction of the humerus. These muscles are therefore not involved in abduction at the gleno humeral joint.

A 68-year-old man is admitted to the hospital due co severe back pain. Radiographic examination reveals evere osteoporo is of the vertebral column with crush fractures of vertebrae L4 and LS. Which of the follow ing parts of the vertebrae are most likely to be fractured in this patient? 0 A. Spinal process 0 B. Vertebral bodies 0 C. Transverse process 0 D. Superior articular process 0 E. Intervertebral disk

0 B. A crush fracture is characterized by compres sion of the entire vertebral body. The wedge fracture is similar in that it affects the vertebral bodies, but it involves sma ll fractures around the perimeter of the vertebral body. Both of these fractures cause reduc tions in overall height. Fracture of the spinal, trans verse, or superio r articular processes can be due to an oblique, transverse, or comminuted fracture. Interver tebral disks are associated with disk herniation, not compression fractures.

A 55-year-old man with severe coughing is ad mitted to the hospital. Radiographic examination reveals tuberculosis of the right lung, with extension to the thoracic vertebral bodies of T6 and T7, producing a "gibbus deformity." Which of the following conditions is most likely also to be confirmed by radio graphic examination? 0 A. Lordosis 0 B. Kyphosis 0 C. Scoliosis 0 D. Spina bifida 0 E. Osteoarthritis

0 B. Kyphosis is cha racterized by a "hunchback" due to an abnormal increase in curvature of the tho racic region of the vertebral column. Lordosis, or "swayback," is an increase in lumbar curvature of the spine. Lordosis can be physiologic, such as seen in a pre0onant woman. Scoliosis is a lateral curvature of the spine with rotation of the vertebrae. Spina bifida is a neural tube defect characterized by failure of clo sure of the vertebral arch. Osteoarthritis is a degen erative disorder that affects the articu lar cartilage of joints and is not specifically related to the thoracic region of the spine.

A 45-year-old man is admitted to the hospital because of evere pain in the back and lower Limb. Radiographic examination reveals spinal stenosis yn drome. Which of the following conditions is most likely to be confirmed by MRl examination? 0 A. Hypertrophy of supraspinous ligament 0 B. Hypertrophy of interspinous ligament 0 C. Hypertrophy of ligamentum flavum 0 D. Hypertrophy of anterior longitudinal ligament 0 E. Hypertrophy of nuchal ligament

0 C. The ligamentum flavum connects the lamina of two ad jacent vertebrae and forms the posterior wall of the vertebral canal. It is the only answer choice that is in direct contact with the vertebral fora men . Therefore, hypertrophy of only the ligamentum flavum would present as spinal stenosis. The supra spinous and interspinous ligaments connect spinous processes. The anterior longitudinal ligament con nects the anterior portion of the vertebral bodies and intervertebral disks. Finally, the nuchal ligament is a thickened extension of the supraspinous ligament above the level of C7.

A 58-year-old male in the intensive care ward exhibited little voluntary control of urinary or fecal activity following a transplant procedure of his left kidney. In addition, physical examination revealed widespread paralysis of his lower limbs. These func tions were essentially normal prior co admission to the hospital. The most likely cause of this patient's problems is which of the following? O A. Injury to the left vertebral artery 0 B. Injury of the grea t radicular artery (of Ada mkiewicz) 0 C. Ligation of the posterior spinal artery 0 D. Transection of the conal segment of the spinal cord 0 E. Division of the thoracic sympathetic chain

16 B. The (great radicular) artery of Adarnkiewicz is important for blood supply to anterior and posterior spinal arteries. The location of this artery should be noted during surgery because damage to it can result in dire consequences, including loss of all sensation and volun tary movement inferior and at the level of the injury. Injury to the left vertebral artery would not be likely due its sup erior location to the surgical site. Ligation of the posterior spinal artery would not occur because of its protec ted location inside the spinal col umn. Transection of the conus medullaris of the spin al cord would not occur as this structure is located at Ll, U levels and is, again, protected inside the spinal col umn. Division of the thoracic sympathetic chain would not be likely as the symptoms described include limb paralysis, which would nor be a consequence of sympathetic disruption.

A 42-year-o ld woman complains of pain and stiff ness in her neck. She was injured sliding into second base headfirst during her company softball game. Ra diographs reveal no fractures of her s pine . However, upon physical examination her right shoulder is droop ing and she has difficulty in elevating that shoulder. If you ordered an MRI, it would most likely reveal soft tissue damage to which of the following nerves? 0 A. Thoraco dorsal nerve 0 B. Spinal accessory nerve 0 C. Dorsal scapular nerve 0 D. Greater occipital nerve 0 E. Axilla ry nerve

16 B. The thoracodorsa l nerve innervates the la tis simus dorsi, which has no action on the shoulder girdle. The spinal accessory nerve is the eleventh cra nial nerve (CN XI) and inne r vates both the trape zius and sternocle idomastoid muscles. The loss of CN XI results in drooping of the sho ulder due to paralysis of the trapezius. In addition to the clinical findings of the MRI, one can test the innervation of th is nerve by asking the patient to shrug his or her shoulders against resistance (testing the trapezius), as well as turning his or her head against resistance (tes ting the sternocleidomastoid). The dorsal scapular nerve in nervates the levator scapu lae muscle, as well as the rhomboids. The greater occipital nerve is a sensory nerve innervating the posterolateral aspect of the scalp . The ax illary nerve is a branch of the bra chia! plexus and innervates the deltoid and teres minor. It is not involved in shoulder elevation.

A 23-year-old male was killed in a high-speed mo tor vehicle collision after racing his friend on a local highway. When the medical examiner arrives upon the scene, it is determined that the most likely cause of death was a spinal cord injury. Upon confirmation by the autopsy, the medical examine r officially reports that the patient's cause of death was a fracture of the pedicles of the axis (C2). Breaking of which of the following ligaments would be most likely implicated in this fatal injury? 0 A. Ligamentum flavum 0 B. Buchal ligament 0 C. Cruciform ligament 0 D. Posterior longitudinal ligament 0 E. Supraspinous ligament

16 C. The pedicles are bony structures connecting the vertebral arches to the vertebral body. The liga mentum flavum runs on the posterior aspect of the vertebral canal and is more closely associated with the lamina than to the pedicles of the vertebrae. Tbe nuchal ligament is a longitudinal extension of the supraspinous ligament from C7 to the occiput, both running on the most posterior aspect of the vertebrae along the spinous processes. The cruciform (also called cruciate) ligament is a stabilizing ligament found in Cl/C2. It attaches to the pedicles and helps anchor the dens in situ, but it has been broken in this case. The posterior longitudinal ligament extends the length of the anterior aspect of the vertebral canal and is anterior to the pedicles.

A 12-year-old child was brought to the emergency department by his parents because he has been suffe r ing from a very high fever and severe stiffness in his back. The initial diagnosis is meningitis. The attending physician orders a lumbar puncture to confirm the di agnosis. Upon microscopic examination of the cerebro spinal fluid , hematopoetic cells are seen. Which of the following ligaments is most likely to be penetrated by the needle? 0 A. Supraspinous 0 B. Denticulate 0 C. Anterior longitudinal 0 D. Posterior longitudinal 0 E. Nuchal ligament

16 D. Lumbar puncture is generally performed at the level of L4, L5. Th e supraspinous ligament ex tends between spinous processes on the dorsal aspect of the vertebrae . The needle would bypass this struc ture. The denticulate ligaments are not correct be cause they terminate with the conus medullaris at the level of L2 and are loc at ed laterally. The anterior lon gitudinal ligament extend s along the most anterior aspect of th e vertebra l bodies and can be reached only ventrally. The posterior longitudinal ligament is present at the correct vertebral level but will be punc tured onJy if the procedure is performed incorrectly as in this case, where hematopoetic cells were aspirated from the vertebral body anterior to the ligament. The nucha l ligam e nt extends cranially from the supraspi nous liga ment in the lower cervical region to the skull.

A 22-year-old man is brought into the emergency department following a brawl in a tavern. He has se vere pain radiating across his back and down his left upper limb. He supports his left upper limb with his right, holding it close to his body. Any attempt to move the left upper limb greatly increases the pain. A radio graph is ordered and reveals an unusual sagittal frac ture through the spine of the left scapula. The fracture extends superiorly toward the suprascapu lar notch. Which nerve is most likely affected? 0 A. Suprascapular nerve 0 B. Thoraco dorsal nerve 0 C. Axillary nerve 0 D. Subscapular nerve 0 E. Suprascapular nerve and thoracodorsal nerve

A. The suprascapular nerve passes through the suprascapular notch, deep to the superior transverse scapular ligament. This nerve is most likely affected in a fracture of the scapula as described in the question. The thoracodorsal nerve runs behind the axillary artery an d lies superficial to the subscapularis muscle and would therefore be protected. The axillary nerve passes posteriorly through the quadra ngular space, which is distal to the suprascapular notch. The subscapular nerve originates from the posterior cord of the brachia! plexus, which is distal to the site of fracture.

A 38-year-old male is admitted lO the emergency department after a car collision. During physical ex amination several lacerations in the back are discov- 6 ered. Pain from lacerat ions or irritations of the skin of the back is conveyed to the cenrral nervous system by which of the following? 0 A. Dorsal primary rami 0 B. Communicating ra mi 0 C. Ventral primary rami 0 D. Ventral roots 0 E. lntercostal nerves

A. General soma tic afferent fibers are conve yed from the skin of the back via the dorsal primary rarni. Comm unica ting rami contain general visceral efferent (sympathetic). fib e rs a nd general visceral afferent fi bers 0£ the a utonomic nervous system. Ventral pri mary rarni convey mixed spinal nerves to/ from all other pans of the body excluding the back, and parts of the head innervated by cranial nerves. The ventral roots contain only effe rent (mo tor) fibers. lntercostal nerves are the ventral rami of Tl to Tll . The ventral ramus of Tl2 is the subcos tal nerve.

A 22-year-old female is diagnosed with Rayn aud 's disease. In such a case the patient suffers chronic vaso spasm in response to cold. This can lead to arterial constriction and painful ischemia, especially in the fingers or toes. Relief from the symptoms in the hands would require surgical division of which of the follow ing neural elements? 0 A. Lower cervical and upper thoracic sympa thetic fibe rs 0 B. Lower cervical and upper thoracic ventral roots 0 C. Lower cervical and upper thoracic dorsal roots 0 D. Lower cervical and upper thoracic spinal nerves 0 E. Bilateral spinal accessory nerves

A. Lower cervical and upper thoracic sympa thetic fibers. The sympathetic division of the a uto nomic nervous system is primarily responsible for vasoconstriction. Separation of ventral or dorsal roots would lead to undesired consequences, such as a loss of motor or sensory activity. Similarly, surgical divi sion of sp inal nerves would also have unwanted con sequences, but such are not related to the increased arterial constriction and the painfu l ischemia in the digits. Division of selected sympathetic chain ganglia, however, would decrease the sympathetic outflow to the upper limbs.

Which nerve fibers carry the sensation of a mos quito bite on the back, just lateral to the spinous pro cess of the T4 vertebra? 0 A. Somatic afferent 0 B. Somatic efferent 0 C. Visceral afferent 0 D. Visceral efferent 0 E. Somatic efferent and visceral afferent

A. Somatic afferents are responsible for convey ing pain, pressure, touch, temperature, and proprio ception to the CNS. Afferent fibers carry only sensory stimuli, whereas efferent fibers convey motor infor mation. Visceral innervation is associated with the autonomic nervous system. Visceral afferents gener ally carry information regarding the physiologic changes of the internal viscera whereas visceral ef ferents deliver autonomic motor function to three types of tissue: smooth muscle, cardiac muscle, and glandular epithelium.

A 62-year-old woman is admitted to the hospital because of her severe back pain. Radiographic exami nation reveals thar the L4 vertebral body has slipped anteriorly, with fracture of the zygapophysial joint (Fig. 1-1). Whar is the proper name of rhis condirion? 0 A. Spondylolysis and spondylolisthesis 0 B. Spondylolisthesis 0 C. Crush vertebral fracture 0 D. Intervertebral disk herniation 0 E. Klippel-Feil syndrome

A. Spondylolisthesis is an anterior disp lace ment crea ted by an irreg ularity in the ant er io r mar gin of the vertebral column such that LS and the overlying L4 (and some ti mes L3) prot rude forward. Spondy lolysis is a condition in which the region be tween the superior and inferior articula r facets (on the posterior arch of the LS vertebra) is damaged or missing, which is not the case in this example. Crush vertebral fracture is a collapse of vertebral bodies as a result of trau ma. lnterverteb ral disk herniations occur when the nucleus pulposus protrudes through the anulus fibrosus into the intervertebral foramen or vertebral canal. The most common protrusion is posterolaterally, where the anulus fibrosus is nor reinforced by the posterior longitudinal ligament. Klippel-Feil sy ndro me resul ts from an abnormal number of cerv ical vertebral bodies.

A 65-year-old male is injured when a vehicle trav eling at a high rate of speed hits his car from behind. Radiographic examination reveals that two of his ar ticular processes are now locked together, a condition known as "facet jumping." In which region of the spine is this injury most likely to occur? 0 A. Cervical 0 B. Thoracic 0 C. Lumbar 0 D. Lumbosacral 0 E. Sacral

A. Spondylolysis, also known as "facet jump ing," is the anterior displacement of one or more vertebrae. This is most commonly seen with the cervi cal vertebrae because of their small size and structure and the oblique angle of the articular facets. Lumbar vertebrae are somewhat susceptible to this problem because of the pressures at lower levels of the spine and the sagitta1 angles of the articular facets. It is much less common in the thoracic vertebrae due to the stabilizing factor of the ribs. It is never seen in the sacral vertebrae because they are fused together.

A 39-year-old male presents with severe neck pain after a whiplash injury, sustained when his car was struck from behind. Radiographic studies reveal trauma to U1e ligament lying on the anterior surface of the cervical vertebral bodies. Which ligament is this? 0 A. Anterior longitudinal ligament 0 B. Ligamentum flavum 0 C. Buchal ligament 0 D. Posterior longitudinal ligament 0 E. Transverse cervical ligament

A. The anterior longitudinal ligament lies anterior to the vertebral bodies along the vertebral column. The ligarnent m flavum connects the lamina of two adjacent vertebrae. The nuchal ligament is a continu ation of the s upras pinous ligament above C7, which connects spinous processes. The posterior longitudi nal ligament lies on the posterior edge of the vertebral bodies. The transverse cervical (cardin al) ligament is associated with the pelvic region of the body and not the spinal column.

A 22-year-old male soccer player is forced to leave the game following a head-to-head collision with another player. He is admitted to the hospital, and radiographic examination reveals slight disloca Lion of the atlantoaxial joi nt. As a result, he experi ences decreased range of motion at that joint. What movement of the head would most likely be severely affected? 0 A. Rotalion 0 B. Flexion 0 C. Abduction 0 D. Extension 0 E. Adduction

A. The atlantoaxial joint is a synovial joint re sponsible for rotation of the head, not flexion , abduc tion, extension, or adduction . The atlanto-occipiral joint is primarily involved in flexion and extension of the head on the neck.

A 40-year-old woman survived a car crash in which her neck was hyperextended when her vehicle was struck from beh ind . At the emergency depart- ment a plain radiograph of her cervical spine revealed a fracture of the odontoid process (dens). Which of the following was most likely injured? 0 A. Anterior arch of the at las 0 B. Poste rior tubercle of the atlas 0 C. Atlanto-occipital joint 0 D. Inferior articular process of the axis 0 E. Anterior tubercle of the atlas

A. The odontoid process, or the dens, projects superiorly from the body of th e axis and articulates with the an terior arch of the atlas. The posterior and anterior tubercles of the atlas are bony eminences on the outer surface . The in fer ior articular facet is where the axis joins to the C3 verteb ra.

A 6-year-old boy is admitted to the hospital with coughing and dyspnea. During taking of the history he complains that it feels like there is glass in his lungs. Auscultation reveals abnorma l lun g sounds. The abnor mal lung sounds are heard most clearly during inhala tion with the scapulae abducted. Which of the follow ing form the borders of a triangu lar space where one should place the stethoscope in order to best hear the lung sounds? 0 A. Latissimus dorsi, trapezius, medial border of scapu la 0 B. Deltoid , levator scap ulae, trapezius 0 C. Latissimus dorsi, external abdominal oblique, iliac crest 0 D. Quadratus lumborurn, internal abdominal oblique, inferior border of the twelfth 0 E. Rectus abdominis, inguinal liga me nt, inferior epigastric vessels

A. The region bounded by the upper border of the Iatissimus dorsi, the lateral border of th e tra pe zius, and the medial border of the scapula is known as the triangle of a usculta tion. Lung sounds can be heard most clearly from this location because mini mal tissue intervenes between the skin of the bac k and the lungs. The deltoid, levator scapulae, and crapezius do not form the borders of the " triangle of auscultation." The latissimus dorsi, external abdominal oblique, and iliac crest form the borde r of Petit's inferior lumbar triangle. The quadrat us lumborum, internal abdominal obliq ue, and inferio r border of the twelfth rib form the border of the Gryn fe ltt 's superior lumbar tria ngle. The rectus ab dominis, inguinal ligament, and inferior epigastric vessels form the border of the Hesselbach tria ngle. Petit, Grynfeltt , and Hesselbach triangles are com mon sites for hernias.

A 27-year-old man is admitted to the emergency department after a car crash. Physical examination re veals weakness in medial rotation and adduction of the humerus. Which of the foJlowing nerves was mo t probably injured? 0 A. Thoracodorsal 0 B. Axillary 0 C. Dorsal scapular 0 D. Spinal accessory 0 E. Radial

A. The thoracodorsal nerve innervates the latis simus dorsi, one of three major muscles that adduct and medially rotate the humerus. The axillary nerve supplies the deltoid muscle, the dorsal scapular sup plies the rhomboids and levator scapulae, whereas the spinal accessory innervates the trapezius. None of these nerves medially rotates or adducts the hu merus. The radial nerve is responsible for the inner vation on the posterior aspect of the a rm. The medial and lateral pectoral nerves and the lower subscapular nerve supply the other two medial rotators of the hume rus.

A 24-year-old female presents with severe head ache, photo pho bia, and stiffness of her back. Physical examination reveals positive signs for meningitis. The attending physician decides to perform a lumbar punc ture to determine if a pathogen is in the CSF. What is the last structure the needle will penetrate before reaching the lumbar cistern? 0 A. Arachnoid mater 0 B. Dura mater 0 C. Pia mater 0 D. Ligamenturn flavum 0 E. Posterior longitudinal ligament

A. When a lumbar puncture is performed, the needle must penetrate the liga mentum flavum, the dura mater, and finally the arachnoid mater to reach the subarachnoid space where the CSF is loca ted . The lumba r cistern is a continuation of the subarachnoid space below the conus medullaris . The pia mater is adherent to the spinal cord, and the pos terior longitu dinal ligament is attached to the posterior aspect of the venebral bodies.

A 65-year-old male complains of severe back pain and inabHity to move his left lower limb. Radiographic studies demonstrate the compression of nerve element at the intervertebral fora.men between vertebrae 15 and S1. Which structure is mo t likely re ponsible for thi space-occupying lesion? 0 A. Anulus fibrosus 0 B. ucleus pulposus 0 C. Posterior longitudinal ligament 0 D. Amerior longitudinal ligament 0 E. Ligamentum flavum

B. Compression of nerves at the inter verteb ral foramen indicates a disk herniation. A disk hernia tion is characterized by protrusion of the nucleus pulposus from the an ulus fibrosus posterolaterally into the spinal canal or intervertebral foramen. The ligaments may be affected by the herniation but are not responsible for the compression of the spinal nerve roots.

A 64-year-old man arrived at the clinic with a severely painful rash and skin eruptions that are local ized entirely on one ide of his body closely following the dermatome level of spinal nerve C7. The patient was diagnosed with herpes zo ter virus. In what struc ture has the virus most likely proliferated to cause the patient's current condition? 0 A. The sympathetic chain 0 B. The dorsal root ganglion of the C7 spinal nerve 0 C. The lateral horn of the C7 spinal cord segment 0 D. Tbe posterior cutaneous branch of the dorsal primary ramus of C7 0 E. The ventral horn of the C7 spinal cord segment

B. Herpes zoster is a viral disease that remains la tent in the dorsal root ganglia of sensory nerves and presents as a painful skin lesion. It is associated only with sensory nerve fibers and has no motor involvement. The only answer choice that is solely responsible for sensory innervation is the dorsal root ganglion.

A 22-yea r-old male is thro wn through a plate glass wall in a fight. Radiologic exa minatio n reveals that the lateral border of his right scapula is shattered. He is admitted to the emergency department, and physical examination reveals difficult y laterally rotating his arm. Which of the following muscles is most prob ably injured? 0 A. Teres major 0 B. Infraspinatus 0 C. Latissimus dorsi 0 D. Trapezius 0 E. Supraspinatus

B. Infraspinatus is responsible for lateral rota tion (along with the teres minor, not a choice here). Teres major is responsible for adduction and medial rotation of the humerus. Latissimus dorsi is respon sible for adduction, extension, and medial rotation of the humerus. Trapezius is an elevator of the scapula and rotates the scapula during abduction of the h u merus above the horizonta l plane. Supras pinatus is responsible for the 0° to 15° of abdu ction.

During a routine physical examination a 65-year old male patient is tested for ease and flexibility of the movements of his lumbar region. Which of th e following movements is most characteristic of the intervertebral joints in the lumbar region? 0 A. Circumduction 0 B. Lateral flexion 0 C. Abduction 0 D. Adduction 0 E. Inversion

B. Lateral flexion is the best answer because other movements of the lumbar portion of the verte bral column are very limited due to the orientation of the articular facets.

A 53-year-old male is admitted to the emergency department due to severe back pain. MRl examination reveals anterior dislocation of the body of the LS verte bra upon the sacrum. Which of the following is the most likely diagnosis? 0 A. Spondylolysis 0 B. Spondylolisthesis 0 C. Herniation of intervertebral disk 0 D. Lordosis 0 E. Scoliosis

B. Spondylo listhesis is an anterior vertebral dis placement created by an irregula rity in the anterior margin of the vertebral column such that LS and the overlying L4 (an d sometimes L3) protrude forward rathe r than being restrained by SL Spon dylolysis is a condi tion in which the region betwee n the superior and infe ri or articular facets (on the posterior arch of the LS vertebra) is damaged or missing, which is not the case in this example. Herniation is a protrusion of the nucleus pulposus through the anulus fibrosus, and this is not assoc ia te d with vertebral dislocation. Lordos is and scoliosis are excessive curvatures that do not involve dislocations.

A 34-year-old woman is admitted to the emer gency department after a car crash. Rad iog raph ic ex amination reveals a whiplash injury in addition to hyperextension of her cervical spine. Which of the following ligaments will most likely be injured? 0 A. Ligamentum flavum 0 B. An terior longitudinal ligament 0 C. Posterior longitudinal ligament 0 0. Anulus fibrosus 0 E. Interspinous ligament

B. The anterior longitudinal ligament is a strong fibrous band that covers and connects the anterolateral aspect of the vertebrae and intervertebral disks; it maintains stability and prevents hyperextension. lt can be rorn by cervical hyperextension. The ligamentum flavum helps maintain upright posture by connecting the laminae of two adjacent vertebrae. The posterior longitudinal ligament runs within the vertebral canal supporting the posterior aspect of the vertebrae and prevents hyperflexion. The anulus fibrosus is the outer fibrous part of an interverteb ral disk. The interspinous ligament connects adjacent spinous processes.

A 53-year-old male was in a head-on vehicle col lision that resulted in compression of the spinal cord by the dens of the axis , with resulting quadriplegia. Which of the following ligaments was most probably torn? 0 A. Anterior longitudinal ligament 0 B. Transverse ligament of the atlas 0 C. Ligamentum flavum 0 D. Supraspinous ligament 0 E. Nuchal ligament

B. The anterior longitudinal ligament runs on the anterior aspect of the vertebrae and is not affec ted. The transverse ligament of the atlas anchors the dens later ally to prevent posterior displacement of the dens . This ligament has been tom in this injury. The ligarnentum flavum is found on the posterior aspect of the vertebral canal and does not contact the an te riorly placed dens. The supraspino us ligament is located along the spi nous processes of the vertebrae. The nuchal ligame nt is a longitudinal extension of the supraspino us liga ment above the level of C7.

A 25-year-old male race car driver is admitted to the emergency department after a severe car crash. Radiographic studies reveal damage to the tip of the transverse process of the third cervical verte bra, with a significantly large pulsa ting hematoma. What artery is the most likely to have been damaged? 0 A. Anterior spinal artery 0 B. Vertebral a rtery 0 C. Ascending cervical arte ry 0 D. Deep cervical artery 0 E. Posterior spinal arteries

B. The anterior spinal artery is located anteriorly along the spinal cord and is nor direc tly associated with the vertebrae. The vertebral arter ies run through the tra nsverse foram ina of cervica l vertebrae C6 through Cl and are the refore most closely associated with in jur y to the tra nsverse processes. The ascending cervical artery is a very small branch from the thyro cervical trunk of the subclavian artery, running on the anterior aspect of the vertebrae. The deep cervical artery arises from the costocervical trunk is also a very sma ll artery and courses along the posterior as pect of the cervical vertebrae. The posterior spinal arteries are dherem to the posterior aspect of the spinal cord.

When a lumbar puncture is performed to sample cerebrospinal fluid, which of the following external landmarks is ilie mo t reliable to determine the posi tion of the L4 vertebral spine? 0 A. The inferior angle of the scapulae 0 B. The iliac crests 0 C. The lowest pair of ribs bilaterally 0 0. The posterior superior iliac pines 0 E. The posterior inferior iliac pine

B. The iliac crests are used as a landmark for lo cating the position of L4 to LS for a lumbar puncture; they are identified and traced medially toward the vertebral column. The inferior angles of the scapulae lie at vertebral level T7; the lowest ribs lead one to Tl2; a line between the posterior superior iliac spines crosses vertebral level S2; the posterior inferior iliac spines lie below S2.

An 18-year -old female passenger injured in a roll over car crash was rushed to the emergency depart ment. After the patient is stabilized she undergoes physical examinatio n. She demonst rates considerable weakness in her ability to flex her neck, associated with injury to CN XI. Which of the following muscles is most probably affected by nerve trauma? 0 A. Iliocostalis thoracis 0 B. Sternocleidomastoid 0 C. Rhomboid major 0 D. Rhomboid minor 0 E. Teres major

B. The iliocostalis thoracis muscle is found in the deep back and functions to maintain posture. It is not associated with neck Ue xion. The sternocleido mastoid muscle is innervated by CN XI and fu nctio ns in conrralateral rotation and bilateral flexion of the neck. Rhombo id ma jor and min or are both innervated by the dorsal scapular nerve and serve to adduct the scapulae. Teres major is inn ervated by the lower sub scapular nerve and serves to medially rotate and ad duct the hume rus.

A 7-year-old female who is somewhat obese is brought to the emergency department because of a soft lump above the buttocks. Upon physical examination you note the lump is located just superior lO the iliac crest unilater ally on the left side. The protrusion is deep to the skin and pliable to the wuch. Which of the following is the most probable diagnosis? 0 A. Tumor of the external abdominal oblique muscle 0 B. Herniation at the lumbar triangle (of Peti t) 0 C. Indirect inguinal hernia 0 D. Direct inguinal hernia 0 E. Femoral hernia

B. The lumbar triangle (o f Petit) is bordered me dially by the latissimus dorsi, laterally by the external abdominal oblique, and infe riorly by the fliac crest. The floor of Petit ' s triangle is formed by the internal abdominal oblique, and this is a possible site of her niation. An indirect inguinal hernia is located in the inguinal canal of the anterior abdominal wall. A direct inguinal hernia is located in the Hesselbach triangle of the anterior abdominal wall. A femoral hernia oc curs below the inguinal ligament. Answer A is not the best answer because this lump is described as soft and pliable, which would not likely indicate a tumor, as tumors tend to be hard masses .

In the event of intervertebral disk herniation in the cervical region, which of the following ligaments is in an anatomic position to protect the spinal cord from direct compression? 0 A. Supraspinous 0 B. Posterior longitudinal 0 C. Anterior longitudinal 0 D. Ligamentum flavum 0 E. Nuchal ligament

B. The posterior longitudinal ligament is the only ligament spanning the posterior aspect of the vertebral bodies and intervertebral disks. With inter vertebral disk herniation, the nucleus pulposus of the intervertebral disk protrudes posterolaterally. The an terior longitudinal ligament traverses the anterior side of the vertebral bodies and thus would not protect the spinal cord from direct compression. The supraspinous and ligamentum flavum ligaments connect the spinous processes and the laminae of adjacent vertebrae, respectively. The nuchal ligament is a continua- tion of the supraspinous ligaments near the C7 vertebrae and runs to the occipital protuberance .

A 65-year-old patient complains of severe, chronic pain from the region of her righ t hip. The patient is admitted to the hospital and a decision is made to per form surgery to avoid prescribing excessive pain medi cation. In such a case, which would the surgeon most likely choose to perform? O A. Division of the ventral primary rami of nerves supplying the affected region O B. Transection of all dorsal primary rami of nerves from the hip area O C. Removal of abdominal sympathetic chain gan glia on the right side O D. Transection of the dorsal rootlets of spinal nerves supplying the right hip O E. Division of lower lumbar and sacral ventral rootlets

B. Transection of all dorsal rootlets of the nerves from the hip area is also know n as a dorsal rhizotomy. This type of surgical procedure is performed to elimi nate pain sensation from whiche ver dermatome level is transected. Because dorsal rootlets contain general sensory afferent fibers, cutting these would eliminate sensation and thus pain. Division of the ventral pri mary rami might result in pain elimination; however, because the fibers in ventral rootlets are mixed, there would also be adverse consequences such as motor and sympathetic and even parasympa the tic deficits depending on the level. Removal of abdominal sym pathetic chain ganglia on the right side would not eliminate pain in the hip area since the fibers for this sensation are general soma tic afferents and the sym pathetic chain contains general visceral efferents and afferents. Transection of dorsal primary rami of spinal nerves would not eliminate pain in the hip because the dorsal rootlets contain mixed fibers that supply only a limited area on the back. Division of lower lumbar and sacral ventral rootlets would not elimi nate pain sensation since these rootlets contain effer ent motor fibers and no afferents.

A male newborn infant is brought to the clinic by his mother and diagnosed with a congenital malforma tion. MRI studies reveal that the cerebellum and me dulla oblongata are protruding inferiorly through the foramen magnum into the vertebral canal. What is this clinical condition called? 0 A. Meningocele 0 B. Klippel-Feil syndrome 0 C. Arnold-Chiari malformation 0 D. Hydrocephalus 0 E. Terhered cord syndrome

C. Arnold-Chiari malformation results from her niation of the medulla and cerebellum into the foramen magnum. Meningocele is a small defect in the cranium in which only the men inges herniate. Klippel-Feil syn drome results from an abnormal number of cervical venebral bodies. Hydrocephalus results from an over production of cerebrospinal fluid, obstruction of its flow, or interference w ith CSF absorp tion . Tethered cord syndrome is a conge nital anomaly caused by a defective closure of the neural tube. This syndrome is characteriz ed by a low conus medullaris and a thick filum terminale.

A 37-year-old pregnant woman is adminisrered a caudal epidural block to alleviate pain during delivery. Caudal epidural block involves injection of local anes thetic into the sacral canal. Which of the following landmarks is mosr commonly used for the ca uda l epi dural block? 0 A. Anterior sacral foramina 0 B. Posrerior sacral fora min a 0 C. Cornua of the sacral hiatus 0 D. Intervertebral foramina 0 E. Medial sacral crest

C. Caudal anesthesia is used to block the spinal nerves that carry sensation from the perineum. This procedure is commonly used by obstetricians to re lieve pain during labor and childbirth. Administration of local anesthetic to the epidural space is via the sacra l hiatus, which opens between the sacral cornua. The anterior sacral foramina are located on the pelvic surface of the sacrum and are not palpable from a dorsal approach . The posterior sacral foramina and interven ebr al foramina are the openings through which sacral nerves exit and are not palpable land marks. The medial sacral crest is cranial to the injec tion site.

In spinal anesthesia the needle is often inserted between the spinous processes of the L4 and LS verte brae to ensure that the spinal cord is not injured. This level is safe because in the adult the spinal cord usuall y terminates at the disk between which of the following vertebral levels? 0 A. T11 and T12 0 B. Tl2 and L1 0 C. L1 and L2 0 D. L2 and L3 0 E. L3 and L4

C. L1 and L2. This is the location of the conus medullaris, a tapered conical projection of the spinal cord at its inferior termination. Although the conus medullaris rests at the level of Ll and L2 in adults, it is often situated at L3 in newborns. The cauda equina and filium terminale extend beyond the conus medullaris.

A 23-year-old woman is admitted to the hospital due to back pain. Radiographic examination reveals that she suffers from a clinical condition affecting her vertebral column . Physical examination and history taking reveals that she suffered from polio and a mus cular dystrophy. Which of the following conditions of the vertebral column will most likely be present in this patient? 0 A. Lordosis 0 B. Kyphosis 0 C. Scoliosis 0 D . Spina bifida 0 E. Osteoarthritis

C. Scoliosis can be a secondary condition in such disorders as muscular dystrophy and polio in which abnormal muscle does not keep the vertebral colu mn's normal alignme nt and results in a lateral cu rvature . Lordosis is increased secondary curvature of the lumbar region. It can be caused by stress on the lower back and is quite common in pregnan cy. Ky phosis is increased primary curvature of the thoracic regions and produces a hunchback deformity. ft can be secondary to tuberculosis, producing a "gibbus deformity," which results in angulated kyphosis at the lesion site. Spina bifida is a congenital defect and would not present as a result of muscular dystrophy or polio. Osteoarthritis most commonly presents with age from normal " wear and tear." It is not likely in a 23-year-old woman.

A 32-year-old mother complains of serious pain in the coccygeal area some days after giving birth. To determine whether the coccyx is involved, a local anesthetic is first injected in the region of the coccyx and then dynamic MRI studies are performed. The MRI reveals coccydynia, which confirms that her coccyx dislocates upon sitting. The local anesthetic is used to interrupt which of the following nerve pathways? 0 A. Visceral afferents 0 B. Somatic efferent 0 C. Somatic afferent 0 D. S ympa the tic preganglionic 0 E. Parasympathetic preganglionic

C. Somatic afferent fibers convey localized pain, typically from the body wall an d limbs. Visceral af ferents convey autonomic nervous system sensory information. Pain from these fibers will present as dull and diffuse. Somatic efferen t fibers convey motor information to skeletal muscle. Sympathetic pregan glionic fibers a re visceral effe re nt fibers and do not contain sensory information . Parasympathetic pregan glionic fibers are also visceral efferents and do not contain sensory information.

A maternal serum sample with high alpha fetoprotein alerted the obstetrician to a possible neura l tube defect. Ultrasound diagnosis revealed a meningo- cele protruding from the back of the child. Which of the following is the most likely diagnosis of this con genital anomaly? 0 A. Cranium bifida 0 B. Spina bifida occulta 0 C. Spina bifida cystica 0 D. Hemothorax 0 E. Arnold-Chiari malformation

C. Spina bifida cystica refers to spina bifida with meningocele and is the correct answer. Cra nium bifida could present with meningocele in the sku ll, but it would not be located in the lower back. Spina bifida occulta is a defect in the formation of the vertebral arches and does not present with me ningocele. Hemothorax refers to blood accumulation in the pleural space surrounding the lungs. Arnold Chiari malformation is a herniation of the medulla oblongata and cerebellum through the foramen mag num and would not present with pathologies in the lower back.

A 1-year-old girl is brought to the clinic for a rou tine checkup. The child appears normal except for a dimpling of the skin in the lumbar region with a tu ft of hair growing over the dimple. You reassure the mother that this condition is seen in 10% to 25 % of births and normally has no ill effects. What is this relatively com mon condition that results from incomplete embryo logic development? 0 A. Meningomyelocele 0 B. Meningocele 0 C. Spina bifida occulta 0 D. Spina bifida cystica 0 E. Rachischisis

C. Spina bifida is a developmental condition re sulting from incomplete fusion of the vertebral arches within the lumbar region. Spina bifida occulta com monly presents asymptomatically with a tuft of hair and a small dimple in the overlying skin. More severe forms (spina bifida cystica) are categorized into three types: Spina bifida cystica with meningocele presents with protrusion of the meninges through the unfused vertebral arches. Spina bifida with meningomyelocele is characterized by protrusion both of the meninges and CNS tissues and is often associated with neuro logic deficits. Rachischisis, also known as spina bifida cystica with myeloschisis, results from a failure of neural folds to fuse and is characterized by protrusion of the spinal cord or spinal nerves and meninges.

A 42-year-old female is diagnosed with constriction of the cervical vertebral canal. A laminectomy of two vertebrae is performed. Which of the following ligaments will most likely also be removed? 0 A. Anterior longitudinal 0 B. Denticulate 0 C. Ligamentum fla vum 0 D. Nuchal 0 E. Cruciate

C. The anterior longitudinal ligament runs along the anterior-most aspect of the vertebral column from Cl to the sacrum and would therefore be unaffected by laminectomy. Denticulate ligaments extend laterally from the pia mater to the arachnoid mater along the length of the spinal cord. The ligamentum flavum is one of the two ligaments found in the vertebral canal and is adherent to the anterior aspect of the vertebral arches. It is thus simultaneously removed upon exci sion of the lamina. The nuchal ligament is a thick longitudinal extension continuing from the supraspi nous ligament at the level of C6 to the external occipi tal protuberance. The cruciate ligament is an incorrect answer because it is located anterior to the spinal cord, and thus would not be involved in laminec tomy.

A 23-year-old college student is admitted co the emergency department after jumping from a SO-foot waterfall. The MRI of his back reveals a lateral shift of the s pinal cord co the le ft. Which of the following structures has most likely been torn to cause the deviation? 0 A. Posterior longitudinal ligament 0 B. Tentorium cerebelli 0 C. DenticuJate liga men ts 0 D . Ligamentum flavum 0 E. Nuchal ligament

C. The denticula te liga ments are lateral exte n sions of pia mater between the dorsal and ventral roots of the spinal nerves that attach to the dura ma ter. These ligaments function to keep the spinal cord in the midline position. The posterior longit udinal ligament supports the posterior aspect of the verte brae within the vertebral canal. The tentor ium cere belli is a layer of dura mater tha t supports the occipi tal lobes of the cerebral hemispheres and covers the cerebellum. The ligamentum flavum helps maintain upright posture by connecting the laminae of two adjacent vertebrae. The nuchal ligament is a th icken ing of the suprasp inous ligaments extending from the C7 vertebra to the external occipital protuberan ce.

A 35-year-old man is admitted to the hospital after a severe car crash. Radiographic examination reveals an injury to the dorsal surface of the neck and a fracture in the medial border of the right scapula. Dur ing physical examination the patient presents with the scapula retracted laterally on the affected side. Which of the following nerves has most likely been injured on that side? 0 A. Axillary 0 B. Long thoracic 0 C. Dorsal scapular 0 D. Greater occipital 0 E. Suprascapular

C. The dorsal scapular nerve (from the ventral ramus of CS) is responsible for innervating rhomboids major and minor. The rhomboids are responsible for medial retraction (add uction) of the scapu la. There fore, if this nerve is damaged, individuals present with a laterally displaced (abducted) scapula. In this case the levator scapular remains functional due to addi tional innervation provided by C3-4 spinal nerves. The axillary nerve innervates the deltoid and teres minor muscles. The deltoid muscle abducts the humerus, and the teres minor laterally rotates the humerus. The long thoracic nerve innervates the serratus anterior, which functions to abduct and upwardly rotate the scapula. The greater occipital nerve is ma.inly sensory and is also contributing to the innervation of the semis pinalis capitis. In addition, greater occipital nerve is implicated in occipital neuralgias . The suprascapular nerve inner vates the supraspinatus and infraspinatus muscles. The supraspinatus abducts the humerus, and the infraspi natus muscles laterally rotate the hwnerus. Injury to any of these other nerves would not present with a laterally retracted scapula.

A 39-year-old woman complains of an inability w reach the top of her head to bru h her hair. History reveals rhat she had undergone a bilateral ma tectomy procedure 2 months earlier. Physical examination dem on trate winging of both of her scapulae. Which nerves were most likely damaged during surgery? 0 A. Axillary 0 B. Spinal accessory 0 C. Long thoracic 0 D. Dorsal scapular 0 E. Thoracodorsal

C. The long thoracic nerve innervates the serra tus anterior, which is responsible for elevation and abduction of the scapula beyond the horizontal level while maintaining its position against the thoracic wall. Along with the thoracodorsal nerve, the Jong thoracic nerve runs superficially along the thoracic wall and is commonly subject to injury during mas tectomy procedures. The axillary nerve, the spinal accessory nerve, and the thoracodorsal nerve supply the deltoid muscle, trapezius muscle, and latissimus dorsi muscles, respectively. The dorsal scapular nerve is responsible for innervation of the rhomboids and levator scapulae. Aside from the long thoracic and thoracodorsal nerves, the remaining nerves do not course along the lateral thoracic wall.

A 19 -year-old presents at the emergency depa rt ment with high fever , severe headache, nausea, and stiff neck for 3 days. The attending physician suspects meningitis and obtains a sample of CSF using a lumbar puncture. From which of the following spaces was the CSF collected? 0 A. Epidural space 0 B. Subdural space 0 C. Subarachnoid space 0 D. Pretracheal space 0 E. Central canal of the spinal cord

C. The su barac hnoid space, containing the CSF, is loca ted between the pia and the arachnoid mater. Neither the epidural space, the subdural space, nor the prerracheal space contai ns CSF. Although the cen rral canal, contained within the substa nce of the spi nal cord, does contain CSF, extraction of CSF from this region would res ult in spinal cord injury. CSF circulates in the area of the s ubarach noid space and can be aspirated only from that location. The subdu ral space is only a potent ial space between the dura and arachnoid mater. The epidural space contains the epidural fat and Batso n's venous plexus and is the preferred site for aspirating CSF for diagnostic pur poses (and epidural anesthesia ). CSF is not located in the pretracheal space .

A 28-year-old pregnant woman is admitted to the obstetrics department for delivery. In the final stages of labor a caudal anesthetic is administered via the sac ral hiatus. Into which of the following spaces in the sacral canal is the anesthetic placed? 0 A. Vertebral canal 0 B. Vertebral venous plexus 0 C. Epidural space 0 D. Subarachnoid space 0 E. Subdural space

C. The vertebral canal is the longitudinal canal that extends through the vertebrae, containing the meninges, spinal cord, and associated ligaments . The vertebral venous plexu s is the valveless network of veins exten ding lon gitudina lly along the vertebral canal. Neither of these answer choices describes a specific space. The epidural space is found superfi cially to the dura mater. It is a fat-filled space extend ing from Cl to the coccyx. The subarachnoid space is a true space containing CSF. It is found within the C S and extends to the level of S2. The subdural space is a potential space between the dura and the arachnoid mater. Norma lly these rwo layers are fused due to the pressure of CSF in the subarachnoid space.

A 45-year-old woman is admitted to the outpa tient clinic for shoulder pain. During physical examina tion she prese nts with weakened shoulder movements. Radiographic examination reveals quadra ngular space syndrome, causing weakened shoulder moveme nts. Which of the following nerves is most likely affected ? 0 A. Suprascapular 0 B. Subscapular 0 C. Axillary 0 D. Rad ial 0 E. Ulnar

C. The weakness in shoulder movement results from denervation of the teres minor and deltoid by the axillary nerve, which passes through the quadran gular space. Quadra ngular space syndrome happens when there is hypertrophy of the muscles that border the qua drangular space or fibrosis of portions of the muscles that are in contact with the nerve.

A 43-year-old male construction worker survived a fall from a two-story building but lost all sensation from his lower limbs and was admitted to the hospital for examination and treatment. Radiographic studies revealed that he crushed his spinal cord at vertebral level C6. Which of the following muscles will most likely be paralyzed? 0 A. Supraspinatus 0 B. Trapezius 0 C. Rhomboid muscles 0 D. Latissimus dorsi 0 E. Deltoid

D. All of the spinal nerves below the C7 verte bral level will be affec ted. This includes the C7 spinal nerve because it exits the vertebral column above the C7 vertebra. The trapezius would be intact because it is innervated by the spinal accessory nerve. The del toid muscles and supraspinatus muscles will be unaf fected because they receive motor supply from CS and C6. The rhombo id muscles should function normally because they are innervated by the dorsal scapular nerve (C.5). The latissimus dorsi muscles would not function normally because they are innervated by the thoracodorsal nerves, which receive contributions especially from the C7 spinal nerves.

A 72-year-old man with cancer of the prostate gland presents with loss of consciousness and seizures. A CT scan is performed and a brain tumor is diagnosed. The tumor spread to the brain from the abdomen via the internal vertebral venous plexus (of Batson ). What fea ture of the plexus aUows this to happen? 0 A. They are the longest veins in the body. 0 B. They have valves that ensure one-way move- ment of blood. 0 C. They are located in the subarachnoid space. 0 D. They are valveless. 0 E. They are located in the subdural space.

D. Batso n's venous plexus is a valveless net work of veins located in the epid ural space of the vertebral canal. The lack of valves can provide a route for the metastasis of cancer (i.e., from prostate or breast to brain) because the flow of blood is not uni directional. The length of Batson ' s plexus is irrelevant to the question. Bis incorrect because Batson 's plexu s does not have valves or one-way movement of blood. Batson's plexus is loca ted within the epidural space, not the subarachnoid or subdural spaces.

Examination of a 3-da y-old male infant reveals protrusion of his spinal cord and meninges from a de fect in the lower back. Which of the following describes this congenital anomaly? 0 A. Avulsion of meninges 0 B. Meningitis 0 C. Spina bifida occulta 0 D. Spina bifida with meningomyelocele 0 E. Spina bifida with meningocele

D. Because the meninges and spinal cord are included in the protrusion, the patient's condition is a classic presenta tion of spina bifida with me ningomy elocele. If the protrusion contains only meninges but no CNS tissue, it is known as spina bifida with menin gocele. Meningitis is an inflammation of the meninges caused by bacteria, viral, or numerous other irritants. It does not cause deformation of vertebrae or result in protrusion of spinal cord contents. Spina bifida oc culta is a normally asymptoma tic condition in which the vertebral lamina fail to fus e completely during embryologic development. A tuft of hair is commonly seen growing over the affected region (usually lumbar in position).

A 32-year-old male elite athlete was lifting heavy weights during an intense training session. The athlete felc severe pain radiaring to the posterior aspect of his right thigh and leg. The patient was taken to the hospi tal where MRI revealed a ruptured L4/LS intervertebral disk. Which nerye is most probably affected? 0 A. L3 0 B. L4 0 C. L2 0 D. LS 0 E. S1

D. In the lumbar region spinal nerves exit the vertebral column below their named vertebrae. In an L4, LS intervertebra1 disk herniation, the LS spinal nerve would be affected as it descends between L4, LS vertebrae to exit below the LS level. L2, L3, and L4 spinal nerves have already exited above the level of herniation; therefore, they would nor be affected by this herniation. An "16" spinal nerve normally does not exist. (The NBME does not allow "made up" structures, but in cases of lumbarization of Sl , some people recognize an L6 nerve. )

A 29-year-old female elite athlete was lifting heavy weights during an intense training session. The athlete felt severe pain radiate suddenly to the posterior aspect of her right thigh and leg. The patient was taken to the hospital where an MRI was performed (Fig. 1-2). Which nerve was most probably affected? 0 A. L3 0 B. L4 0 C. L2 0 D. LS 0 E. S1

D. In this MRI a posterolateral herniation be tween L4/ LS exists. In the lumbar region, spinal nerves exit the vertebral column below their named vertebrae. In an L4/ LS ioterve rtebral disk herniatio n, the LS spinal nerve would be affected as it descends between L4/ LS vertebrae to exit below the LS level.

A 66-year-old female had been diagnosed with a rumor on her spine. She has started to retain urine and is experiencing decreased anal and rectal tone. Both of these symptoms are signs of conus medullaris syn drome. At which of the following vertebral levels is the tumor probably located? 0 A. L3/ L4 0 B. L3 0 C. L4 0 D. Tl2 to L2 0 E. Tll

D. The conus medullaris is located at the Ll-2 vertebral level; therefore, any cho ice that contains that region is the correct answer. L3-4 is a common location to perform lumbar puncture, bur it is caudal to the apex of the conus medullaris. L3 and L4 are caudal to the conus medu llar is. T ll is superior to the conus medullaris.

A 69-year-old female visits her physician due to severe neck pain. Radiographic studies reveal bony growths (osteo phytes ) in the inte rvert ebr al fora men berween vertebrae C2 and C3. Which of the follow ing muscles would be most likely affected by this condition? 0 A. Rhomboid 0 B. Serratus anterior 0 C. Supraspinatus 0 D. Diaph ragm 0 E. Latissimus dorsi

D. The diaphragm is innervated by the phrenic nerve, which arises from C3 to CS. The rhom boid, serratus anterior, supraspinatus, and latissimus dorsi are innervated by the ventral rami of the brachia! plexus (CS to Tl).

A 42-year-old male is struck in the back, ruptur ing the internal vertebral venous plexus (of Batson). Rad iographic studies reveal a hemarnma causing com pression of the spinal cord. When aspirating the excess blood, the physician performing the procedure must stop the needle just before puncturing which of the fol lowing structures? 0 A. Spinal cord 0 B. Pia mater 0 C. Arachnoid mater 0 D. Dura mater 0 E. Ligamentum flavum

D. The internal vertebral plexus (of Batson ) lies external to the dura mater in the epidural space. To aspirate excess blood, the physician must pass the needle through the ligamentum flavum to reach the epidural space wherein the blood would accumulate. The spinal cord, pia mater, and arachnoid mater are located deep to the epidural space.

Following a car crash a 47-year-old female com plains of severe headache and back pain. Radio graphic examination reveals bleeding of the internal venebral venous plexus (of Batson), resulting in a large hematoma. In what space has the blood most likely accumulated? 0 A. Subarachnoid space 0 B. Subdural space 0 C. Central canal 0 D. Epidural space 0 E. Lumbar cistern

D. The internal vertebral plexus (of Batson) sur rounds the dura mater in the epidural space; hence, the bleeding would cause the hematoma in that space. The subarachnoid space, containing the CSF, is located between pia and arachnoid mater. A sub arachnoid bleed would most likely result from a rup tured intercerebral aneurysm. A subdural hematoma would result most likely from a venous bleed from a torn cerebral vein as it enters the superior sagittal venous sinus within the skull. The central canal is located within the gray matter of the spinal cord. The lumbar cistern is an enlargement of the subarachnoid space between the conus medullaris of the spinal cord and the inferior end of the subarachnoid space.

A 34-year-old pregna11t woman in the maternity ward was experiencing considerable pain during labor. Her obstetrician decided to perform a caudal epidural block within the sacral canal. What are the most im portant bony landmarks used for the administration of such anesthesia? 0 A. lschial tuberosities 0 B. Ischial spines 0 C. Posterior superior iliac spines 0 D. Sacral cornua 0 E. Coccyx

D. The sacral cornua lie on either side of the sacral hiatus, from which one can gain access ro the sacral canal. This is the best landmark for administra tion of anesthesia. The ischial tuberosities are more commonly used as landmarks for a pudenda! nerve block. The ischial spines cannot be palpated. The posterior superior iliac spines, though palpable, are not proximal enough for an epidural block within the sacral canal. The coccyx is not part oi the sacral canal.

A 54-year-old woman is admitted to the emer gency department due to increasing back pain over the preceding year. MRI reveals that her intervertebral disks have been compressed. It is common for the disks to shrink in people older than 40, and it can result in spi nal stenosis and disk herniation. At which locations are the spinal nerves most likely to be compressed? 0 A. Between the denticu la te ligaments 0 B. As they pass through the vertebral foramen 0 C. Between the superior and inferior articular facets 0 D. Between inferior and superior vertebral notches 0 E. Between the superior and infe rior intercosto- vertebral joints

D. This question tests anatomic knowledge re lating to typical vertebrae and the spinal cord. Inter vertebral disk herniations occur when the nucleus pulposus of the intervertebral disk protrudes through the anulus fibrosus into the intervertebral foramen or vertebral canal. The most common protrusion is pos terolatera lly, where the anulus fibrosus is not rein forced by the posterior longitudinal ligament. The infe rior and superior verteb ral notches frame the in tervertebral foramen, so this is the most likely loca tion of compression. The denticulate ligaments are lateral extensions of pia mater that anchor to the dura mater, and they hold the spinal cord in position within the subarachnoid space. The vertebral foramen is the canal through which the spinal cord passes; whUe this may also be a place of com pression , it is not the most likely site of her niation. Articular facets are the locations where vertebral bodies articulate with each other. lmercostovertebral joints are loca tions where vertebral bodies articulate with ribs.

A 15-year-old female was suspected to have men ingitis. To obtain a sample of cerebrospinal fluid by spinal tap in the lumbar region (lumbar puncture), the tip of the needle must be placed in which of the follow ing locations? 0 A. ln the epidural space 0 B. Between anterior and posterior longitudinal ligaments 0 C. Superficial to the ligamentum flavum 0 D. Between arachnoid mater and dura mater 0 E. ln the subarachnoid space

E. Cerebrospinal fluid is found within the sub arachnoid space and is continuous with the ventricles of the brain (CSF flows from the ventricles to the sub arachnoid space). The epidural space, positioned be tween the dura mater and periosteum, is characterized by fat deposits and contains the internal vertebral ve nous plexus (of Batson). The subdural space, between the arachnoid mater and dura mater, exists only as a potential space and does not contain cerebrospinal fluid . The anterior and posterior longitudinal ligaments traverse the length of the vertebral body.

A 4S-year-old woman states that she ha experi enced moderate pain for 2 years over her left lower back, pain that radiates to her left lower limb. She states that after lifting a case of soft drinks, the pain became intense. She was admitted to the emergency department. Radiographic examination revealed disk herniation between vertebral levels L4 and LS. Which of tl1e following nerves was most likely affected by the disk herniation? 0 A. L1 0 B. L2 0 C. L3 0 D. L4 0 E. LS

E. Disk herniation in the lumbar region between L4 and LS affects the LS spinal nerve roots. Even though the L4 spinal nerve root lies directly between the L4 and LS vertebrae, it exits from the spinal canal superior to the intervertebral disk, whereas the LS spinal nerve root lies directly posterior to the disk.

A 5-year-old boy is admitted to the hospital be cause of pain in the upper back. Radiographic examina tion reveals abnormal fusion of the CS and C6 verte brae and a high-riding scapula. Which of the following conditions is characteristic of his symptoms? 0 A. Lordosis 0 B. Kyphosis 0 C. Scoliosis 0 D. Spina bifida 0 E. Klippel-Feil syndrome

E. Klippel-Feil syndrome is a congenital defect in which th e re is a reduction, or extensive fusion, in the number of cervical vertebrae. lt often manifes ts as a short, stiff neck with limited morion. Lordosis is an abnormal increase in lum bar curvature. Kyphosis l"hunc hback") is an abnormal increase in thoracic curvature. Scoliosis is a lateral curvature. Spina bifida often presents with deformities in the lumbar region.

A 24-year-old patient suffered a lower back strain after a severe fall while snow skling. MRI studies reveal inJury to the muscles responsible for extending and laterally bending the trunk. What arteries provide blood supply for these muscles? 0 A. Subscapular 0 B. Thoracodorsal 0 C. Anterior intercostal 0 D. Suprascapular 0 E. Posterior intercostal

E. Posterior intercostal arteries supply the deep back muscles that are responsible for extending and laterally bending the tru nk. The subscapular supplies subscapularis muscle, the thoracodorsa1 supplies la tissimus dorsi, the anterior intercos tal supplies the upper nine intercostal spaces, and the suprascapular supplies supraspinatus and infraspinatus muscles. These muscles are not responsible for extension and lateral flexion of the trunk.

A 20-year-old hiker suffers a deep puncture be tween the trapezius and latissimus dorsi muscles on the right lateral side of his back. Upon admission to the 5 hospital, physical examination reveals weak adduction and medial rotation of his arm. Which of the following muscles is most probably injured? 0 A. Teres mino r 0 B. Triceps brachii 0 C. Supraspinams 0 D. lnfraspinatus 0 E. Teres major

E. Teres major is responsible for adduction and medial rotation of the humerus. Teres minor is re spons ible for lateral rotation of the humerus. Triceps brachii is responsible for extension of the forearm. Supraspinatus is responsible for the 0° to 15° of abduction, and infr asp inatus is a lateral rOlator.

A 35-year-old male pedestrian is crossing a busy intersection and is hit by a truck. He is admitted to the emergency department, and a CT scan reveals a dislo cation of the fourth thoracic vertebra. Which of the following costal structures is most likely also involved in the injury? 0 A. Head of the fourth rib 0 B. Neck of the fourth rib 0 C. Head of the third rib 0 D. Tubercle of the third rib 0 E. Head of the fifth rib

E. The T4 thoracic vertebra articulates with the head of the fifth rib. The head of the rib has two fac ets. The rib articulates with the superior facet on the body of its own vertebra (fourth rib articulates with the superior facet T4 vertebra ) and with the inferior facet on the body of the vertebra above (fourth rib articulates with the infer ior facet of T3 vertebra). Tak ing the T4 vertebra into consideration, the superior facet of this vertebra ar ticulates with the head of the fourth rib and the inferior facet articulates with the head of the fifth rib. The head of the fourth rib has two points of articulation (a joint with the vertebral body and costotransverse join t) on T4, so when it is injured it moves as a unit, whereas the fifth rib has only one articulation with T4.

A 26- year-old man painting his house slipped and fell from the ladder, landing on the pavement below. Af te r initial examination in the emergency department, the patient is sent to the radiology department. Radio graphs reveal that the portion of his left scapula that forms the tip, or point, of the shoulder has been frac tured. Which part of the bone was fractured? 0 A. Coracoid process 0 B. Superior angle of the scapula 0 C. Glenoid 0 D. Spine of the scapula 0 E. Acromion

E. The acromion (the highest point of the shoul der) is the part of the scapula that forms the "point" of the shoulder. The coracoid process is located more medially. The superior angle of the scapula is loca ted near the midline of the back. The glenoid of the scapula articulates with the head of the humerus to form the glenohumeral joint. The spine of the scapula is located posteriorly and separates supraspinous and infraspinous fossae.