Chapter (3) Head and Neck Anatomy

66. Inferior alveolar nerve injury can occur: a. During local anesthesia (needle penetration). b. During incision (by scalpel). c. During flap reflection (by stretching its mental branch). d. During osteotomy preparation (by drills). e. During implant insertion (by compression). f. All of the above

f: Dental specialists and general practitioners who place implants must discuss the possibility of nerve injury with the patient and include this possibility in the informed consent form. Detailed knowledge of the related anatomy, careful planning using CT scan images and diagnostic wax-ups, the use of all available tools to perform the surgery accurately (ie, drill stoppers, computer-generated surgical guides), and careful manipulation of soft tissue can help in minimizing to a great extent the incidence of nerve injury

71. The mental nerve provides sensory supply to the: a. Chin b. Lower lip c. Labial mucosa near the mandibular anterior teeth d. Lingual mucosa near the mandibular anterior teeth e. Skin over the body of the mandible f. Skin over the body of the maxilla g. a, b, c, and e h. All of the above except f i. All of the above

g: The mental nerve exits the body of the mandible through the mental foramen, which is usually located between the apices of the first and second mandibular premolars. As such, it provides sensory supply to the chin, lower lip, labial mucosa near the mandibular anterior teeth, and the skin over the body of the mandible.

70. Prevention measures for arterial injury to the floor of the mouth should include but are not limited to: a. Good knowledge of the fine regional arterial anatomy. b. Obtaining a good-quality panoramic radiograph. c. Appropriate clinical procedures, which must be carried out with the utmost attention, because the simplest implant procedure can trigger extremely serious complications. d. Proper selection of the diameter and length of the implant per the available alveolar ridge as well as the appropriate angulation of the implant. e. Adequate training in implant surgery and in medical emergencies. f. Thorough evaluation of the lingual side of the mandible, including the submandibular fossa and the accessory lingual foramina. g. Digital palpation of the lingual mandibular surface, which can help to detect any pronounced concavity in the anterior or posterior areas of the mandible. CT scanning is highly recommended. h. All of the above except b and f i. All of the above

i: All of the above

75. TRUE OR FALSE: Flap-releasing incisions mesial to the mental nerve should terminate 5 mm inferior to the mucogingival junction to avoid possible injury to major branches of the mental nerve.

False: Flap-releasing incisions mesial to the mental nerve should terminate just superior to the mucogingival junction to avoid possible injury to major branches of the mental nerve

85. TRUE OR FALSE: All veins have valves.

False: Most but not all veins (including in the venae cavae and head) have valves inside them to prevent the backflow of blood. Failure of these venous valves permits backflow between movements. As a sequence, the venous pressure increases and the veins grow large, a condition known as varicose veins. *The ophthalmic and facial veins are frequently stated to be devoid of valves, facilitating the spread of infection from the mid-face to the cavernous sinus.

63. TRUE OR FALSE: To avoid cutting the lingual nerve, the distal releasing incision in the retro-molar (triangle) pad area should be 10 degrees toward the buccal (not straight), because the nerve might be laying on the retromolar pad.

False: To avoid cutting the lingual nerve, the distal releasing incision in the retromolar (triangle) pad area should be 30 degrees toward the buccal (not straight), because the nerve might be laying on the retromolar pad. In addition, the lingual side of the flap in the posterior mandibular region should be reflected carefully and gently, and lingual releasing incisions should be avoided.

84. TRUE OR FALSE: Just like arteries, veins do not collapse.

False: Unlike arteries, veins collapse when they are empty. When they are lower than the heart, they become full of blood and stand out beneath the skin. When the arm is raised, the veins normally collapse at a level approximately 9 cm above the level of the heart. Raising an injured part of the body above the level of the heart will stop bleeding from veins but not from arteries.

76. TRUE OR FALSE: The existence of the mandibular incisive canal in the anterior mandible can be problematic; as an extension of the inferior mandibular nerve, it should be considered to contain the same neurovascular elements, and thus osteotomies should not be made through this canal. Damage to the mandibular incisive nerve will result in paresthesia of the corner of the lip.

TRUE: At the vicinity of the molars, the inferior alveolar nerve typically splits into the mental nerve (to supply the skin of the mental foraminal region, the lower lip, the mucous membrane, and the gingiva) and the incisive nerves (to supply the mandibular anterior teeth). However, in some cases, the incisive nerve might present as a true canal with large lumen (0.48 to 2.90 mm) that extends anteriorly and inferiorly from the mental foramen, located 8 to 10 mm from the inferior border of the mandible. This canal can be problematic because, as an extension of the inferior mandibular nerve, it should be considered to contain the same neurovascular elements; thus, osteotomies should not be made through this canal. The incisive canal cannot be detected clearly on conventional radiography, so CT scans are recommended for proper assessment. It is important to note that in the resorbed mandible, the position of the incisive canal (if it is present) is expected to be closer to the alveolar crest. In conclusion, the incisive canal should always be taken into consideration when planning for implant placement in the intraforaminal area.

56. TRUE OR FALSE: The greater palatine neurovascular bundle is localized at the junction of the vertical and horizontal palatal walls of the vault.

True

83. TRUE OR FALSE: Veins do not pulsate.

True

79. TRUE OR FALSE: Chin block graft harvest should not be attempted in D1 bone

True: D1 bone will be impossible to harvest without complications (eg, possible through-and-through window formation upon harvesting or even mandibular fracture)

74. TRUE OR FALSE: The height of the mental foramen can be used as available bone height without surgical risk because the inferior alveolar nerve always rises as it approaches the mental foramen (compared with its height in the molar region).

True: Even if the implant is placed all the way to the superior border of the mental foramen (as seen on a panoramic radiograph; A), in reality it would be located lingual to it (B).

61. TRUE OR FALSE: When indicated for ideal prosthetic planning, excising the incisive/nasopalatine nerve and the blood vessels of the incisive canal and subsequently placing bone graft material for immediate or delayed implant placement is a viable technique that can be performed without detriment to the patient

True: In some cases, the location of the incisive canal may prevent the placement of dental implants to replace missing maxillary central incisors. The nerve and the artery of the incisive canal anastomose with the greater palatine artery and nerve, permitting immediate revascularization and a gradual reinnervation of the region within 3 to 6 months. Nonetheless, loss of sensation in the anterior palate is a possibility, and patients should be warned about it, although this is rarely a cause of patient complaint.

65. TRUE OR FALSE: Unlike the maxillary and the ophthalmic nerves (both entirely sensory), the mandibular nerve has both sensory and motor divisions

True: The inferior alveolar nerve carries motor fibers for the mylohyoid muscle and the anterior belly of the digastric muscle and sensory fibers that enter the canal through the mandibular foramen, giving inferior dental branches to the mandibular teeth and exiting through the mental foramen under the name mental nerve. Damaging the inferior alveolar nerve will alter the sensation to areas supplied by it and by the mental nerve.

59. TRUE OR FALSE: When performing sinus bone augmentation using the crestal approach with simultaneous implant placement, it is recommended that 5 mm of bony height exist under the sinus floor.

True: The judgment of the clinician on the treatment planning of the posterior maxilla (and other areas of the mouth) is paramount, because each clinical case is unique; however, guidelines are always helpful in keeping practitioners on a path that will most likely be successful. Considering the poor quality of the bone in the posterior maxilla, the simultaneous crestal bone augmentation approach with implant placement should not be attempted with less than 5 mm of bony height so as to minimize the possibility of implant migration into the sinus cavity during the procedure or postoperatively

86. TRUE OR FALSE: Blood supply to the nasal cavity is received from both the internal carotid and the external carotid arteries.

True: The nasal cavity receives its blood supply through the internal carotid artery via the anterior and posterior ethmoid arteries (branches of the ophthalmic artery) and through the external carotid artery via the sphenopalatine and greater palatine arteries, all of which are branches of the maxillary artery.

53. TRUE OR FALSE: The pterygoid venous plexus is of special importance to dentists because if the needle is over inserted during posterior superior alveolar block, it may penetrate the pterygoid plexus of the vein and the maxillary artery in the infratemporal fossa, thus causing hematoma.

True: The pterygoid venous plexus is situated on the medial side of the mandibular ramus within the pterygoid muscles. It is linked to the facial vein via the deep facial vein, the retro-mandibular vein via the maxillary vein, and the cavernous sinus via the sphenoidal emissary vein. The pterygoid plexus drains into the jugular veins. This plexus is of a special importance to dentists because if the needle is over-inserted during posterior superior alveolar block, it may penetrate the pterygoid plexus of the vein and the maxillary artery in the infratemporal fossa, thus causing hematoma. This results in extraoral swelling a few minutes after the injection. The hematoma will cause tissue tenderness and discoloration, which will last until the blood is broken down by the body, and possible spread of infection to the cavernous venous sinus if the needle is contaminated. A hematoma can also result during other blocks, such as the infraorbital and the inferior alveolar blocks. To avoid injection into blood vessels, aspiration should always be attempted in all injections.

28. The paranasal sinus most developed at birth is the: a. Maxillary sinus b. Ethmoidal sinus c. Frontal sinus d. Sphenoidal sinus

a: Averaging 8 X 4 X 4 mm, the maxillary sinus is the most developed sinus at birth. The sinus cavity expands rapidly throughout the first year of life, extending laterally to the infraorbital nerve (mid-pupillary line) by 12 months of age. The other sinuses are less developed at birth, with the frontal sinuses often not developing until adolescence.

72. The inferior alveolar nerve usually courses anterior to the mental foramen, turning posteriorly and superiorly to exit the mental foramen. Because of this usual path (anterior loop), the nerve may be as much as: a. 3 mm anterior to the mental foramen. b. 5 mm anterior to the mental foramen. c. 7 mm anterior to the mental foramen

a: Because the nerve may be as much as 3 mm anterior to the mental foramen, if an implant is to be placed mesial to and below the level of the foramen, the most posterior extent of the implant should be at least 5 mm anterior to the mesial aspect of the foramen to avoid drill penetration though the anterior loop. The pilot drill should penetrate the crestal bone 7 to 8 mm anterior to the most mesial aspect of the mental foramen (3 mm for the loop + 2 mm of safety zone + the radius of the implant [R]).

47. What effect does the angle between the buccal alveolus (lateral maxillary wall) and the palatal alveolus (medial maxillary wall), as viewed from the anterior perspective, have on membrane perforation rates in a lateral window approach? a. The narrower the angle, the higher the perforation rate. b. The wider the angle, the higher the perforation rate. c. The narrower the angle, the lower the perforation rate. d. There is no correlation between this angle and perforation rate.

a: Cho et al found that when this angle was greater than 60 degrees, there were no perforations. With an angle of 30 to 60 degrees, they found a 29% perforation rate. When the angle was less than 30 degrees, they found a 63% perforation rate.

40. Hypoplasia of the maxillary sinus occurs in about what percentage of patients? a. 6% b. 19% c. 25% d. 43%

a: Hypoplastic maxillary sinuses are relatively rare and are thought to be related to failure of pneumatization due to deficient bone absorption or obstruction of the sinus. Hypoplasia is most commonly seen in patients with cystic fibrosis, childhood facial trauma, or maxillary teeth that fail to erupt.

6. Which muscle of mastication inserts into the pterygoid tuberosity on the medial surface of the angle of the mandible? a. Medial pterygoid muscle b. Lateral pterygoid muscle c. Temporalis muscle d. Masseter muscle e. Buccinator muscle

a: Medial pterygoid muscle

32. Creating a lateral window too high on the maxillary sinus wall puts which of the following at risk? a. The infraorbital nerve b. The roots of the maxillary molars c. The posterior superior alveolar artery d. The natural ostium of the maxillary sinus

a: The infraorbital nerve (second division of the trigeminal nerve [CN V]) exits through the infraorbital foramen high on the anterior face of the maxilla. This is located at approximately the mid-pupillary line. Care must be taken when elevating the soft tissues superiorly during a lateral window approach to avoid injury to this nerve, which gives sensation to the upper lip, cheek, maxillary sinus, and teeth

80. TRUE OR FALSE: The pulmonary veins in the chest carry oxygenated blood from the lungs to the left side of the heart. a. True. Although arteries usually carry oxygenated blood, the pulmonary veins are an exception. b. False. Veins carry only deoxygenated blood.

a: The majority of veins in the body carry deoxygenated (blue) blood and return blood to the heart from the various organs and tissues of the body. However, there are two exceptions: (1) The pulmonary veins in the chest carry oxygenated blood from the lungs to the left side of the heart. (2) The portal vein carries nutrient-rich blood from the intestines to the liver

24. The mandibular division of the trigeminal nerve (V3) passes through the foramen ovale into the: a. Infratemporal fossa b. Pterygopalatine fossa c. Orbit d. Nasal cavity e. Oral cavity

a: The mandibular division of the trigeminal nerve enters the infratemporal fossa, where it sends motor branches to the muscles of mastication and sensory branches to the tongue, mandibular teeth, oral cavity, and skin of the lower and lateral face

22. The action of the medial pterygoid muscle is to: a. Elevate the mandible. b. Tense the soft palate. c. Elevate the soft palate. d. Elevate the hyoid bone. e. Retract the mandible

a: The medial pterygoid muscle forms a sling with the masseter muscle to elevate the mandible.

All of the following bones form a part of the lateral nasal wall EXCEPT the: a. Ethmoid b. Maxilla c. Palatine d. Inferior concha e. Vomer

e: Vomer

17. Which of the following drains into the inferior meatus of the nasal cavity? a. Nasolacrimal duct b. Frontal sinus c. Ethmoidal sinus d. Sphenoidal sinus e. Maxillary sinus

a: The nasolacrimal duct drains tears from the medial corner of each eye into the inferior meatus.

38. The bilayered secretory blanket lining the sinus membrane consists of which two layers? a. A superficial "gel" layer and an inner "sol" layer b. A superficial "sol" layer and an inner "gel" layer c. A superficial "gel" layer and an inner "mucinous" layer d. A superficial "sol" layer and an inner "mucinous" layer

a: The secretory blanket consists of an inner "sol" layer, which is serous and rich in proteins, immunoglobulins, and complement. Floating on this is the more superficial "gel" layer, which is a viscous mucus that is swept across the respiratory mucosal surface by the action of the cilia.

52. Compared with the mucosa of the nasal cavity, the mucosa of the maxillary sinus: a. Is thinner. b. Contains more goblet cells. c. Has areas of squamous mucosa. d. All of the above

a: The sinus membrane of the maxillary sinus is thinner than the lining of the nasal cavity (usually so thin that it cannot be seen on a CT scan). The nasal cavity mucosa contains more goblet cells and thus produces more mucus than the sinus lining. The anterior nasal mucosa transitions to squamous mucosa and serves a protective function

10. Which bone forms the inferior and posterior parts of the nasal septum? a. Vomer b. Ethmoid c. Palatine d. Temporal e. Sphenoid

a: Vomer

73. In a mandible with extensive resorption, the position of the mental foramen might be on the crest of the ridge. In such a case, care should be taken not to harm the mental nerve, which can be accomplished by placing the crestal incision: a. Slightly toward the lingual. b. Slightly toward the buccal. c. In the middle of the ridge. The crestal incision must always be mid-crestal.

a: When the mental foramen lies on the crest of the ridge, the crestal incision should be placed slightly toward the lingual and a full-thickness flap gently reflected until the foramen is identified. In some scenarios, it is recommended not to open a flap at all but rather to follow a flapless insertion protocol to avoid damaging the mental nerve or any of its branches by the flap reflection.

13. Which is the only laryngeal cartilage to completely encircle the airway? a. Thyroid cartilage b. Cricoid cartilage c. Epiglottic cartilage d. Arytenoid cartilage e. Corniculate cartilage

b. Cricoid cartilage

31. The maxillary sinus drains into which of the following intranasal structures? a. The inferior meatus b. The middle meatus c. The superior meatus d. The sphenoethmoidal recess

b: The maxillary sinus drains into the middle meatus, as do the frontal sinus and the anterior ethmoidal sinuses. The nasolacrimal duct drains into the inferior meatus. The posterior ethmoidal sinuses drain into the superior meatus. The sphenoidal sinus drains into the sphenoethmoidal recess.

37. Which of the following is true of accessory maxillary ostia? a. They may be located posterior or anterior to the natural ostium. b. They are found in up to 25% of sinuses. c. They ensure that the sinus will not be diseased. d. They are a result of incomplete bony formation of the medial maxillary wall.

b: Accessory sinus ostia occur in up to 25% of sinuses. These are formed through incomplete bony development of the medial maxillary wall and, while typically located posterior to the natural ostium, may also be found anterior to it. Because the cilia are programmed to sweep mucus to the natural ostium, the presence of an accessory ostium is largely ignored and does not prevent development of sinus disease related to natural ostium obstruction

49. The structure indicated by the white arrow occurs in about what percentage of patients? a. 12% b. 33% c. 62% d. 97%

b: As described by Underwood in 1910, bony septa arising from the floor of the maxillary sinus are relatively common, occurring in about one-third of patients.

3. A patient is affected by left-side Bell's palsy. Which of the following problems does this patient likely have? a. He is unable to open his left eye. b. He is unable to raise his eyebrow on the left side. c. He is unable to protrude his tongue to the right. d. He is unable to feel pressure on his left cheek.

b: Cranial nerve (CN) VII, the facial nerve, exits the stylomastoid foramen and is responsible for the muscles of facial expression, including the occipitofrontalis muscle, which elevates the eyebrows.

62. Although the buccolingual position of the inferior alveolar canal in the alveolar bone is variable, the distance from the canal to the medial aspect of the buccal cortical plate (medullary bone thickness) was found to be greatest at the: a. Mesial half of the first molar. b. Distal half of the first molar. c. Mesial half of the second molar. d. Distal half of the second molar.

b: Distal half of the first molar (mean: 4 mm). When larger ramus block grafts are planned, the anterior vertical cut should be made in this area (distal half of the first molar). The mean vertical distance between the superior edge of the canal and the cortical surface along the external oblique ridge is 7 mm in the second molar region, 11 mm in the third molar region, and 14 mm at the base of the coronoid process. Therefore, when a smaller graft size is required, the harvest may be made higher on the ramus, which is usually further from the canal

36. As viewed from inside the sinus, the natural ostium of the maxillary sinus is located: a. Low on the medial wall. b. High on the medial wall. c. Low on the anterior wall. d. Low on the posterior wall.

b: High on the medial wall

5. Which muscle of mastication inserts into the condylar process of the mandible and its articular disc and the capsule of the temporomandibular joint (TMJ)? a. Medial pterygoid muscle b. Lateral pterygoid muscle c. Temporalis muscle d. Masseter muscle e. Buccinator muscle

b: Lateral pterygoid muscle

27. Which of the following arteries is a direct branch of the external carotid artery? a. Posterior cerebral artery b. Occipital artery c. Labyrinthine artery d. Ophthalmic artery e. Middle meningeal artery

b: Occipital artery

25. The maxillary division of the trigeminal nerve (V2) passes through the foramen rotundum into the: a. Infratemporal fossa b. Pterygopalatine fossa c. Orbit d. Nasal cavity e. Oral cavity

b: Pterygopalatine fossa

69. If the submandibular fossa is perforated with subsequent bleeding, what should be the first action taken by the operator? a. Stop the bleeding. b. Keep the airway open. c. a and b d. None of the above, as the bleeding is not life threatening and the airway will not be affected by this complication.

b: Securing and maintaining an adequate airway should be given the highest priority. The implant surgeon should be prepared to deal with the possibility of airway obstruction, which can occur very rapidly. The clinical signs of airway obstruction (tachypnea, dyspnea, hoarseness, cyanosis, drooling) can be hidden until there is significant airway occlusion. Persistent intraoral bleeding can cause mechanical pressure to the pharyngeal lumen and consequent airway obstruction, which poses a serious threat to the patient's life. The airway can be secured by nasotracheal, orotracheal, or emergency tracheotomy or cricothyrotomy (when endotracheal intubation is impossible due to extensive hematoma). Manual tongue decompression and tactile intubation have been successful in one report during hemorrhagic swelling of the tongue.

11. Which bone forms the superior and posterior parts of the nasal septum? a. Volmer b. Ethmoid c. Palatine d. Temporal e. Sphenoid

b: The ethmoid bone, through its perpendicular plate, makes up the superior and posterior parts of the nasal septum (see illustration in question #10).

45. The sensory innervation of the maxillary sinus, maxillary teeth, lips, and cheek is from what nerve? a. First division of the trigeminal nerve (V1) b. Second division of the trigeminal nerve (V2) c. Third division of the trigeminal nerve (V3) d. Greater petrosal nerve

b: The first division of the fifth cranial nerve (V1, or the ophthalmic nerve) gives sensation to the scalp, forehead, periorbital structures, frontal sinus, and dorsal nose. The second division (V2, or the maxillary nerve) gives sensation to the cheek, lateral nose, interior nose and sinuses, palate, and maxillary teeth. The third division (V3, or the mandibular nerve) gives sensation to the lower lip, mandibular teeth and gums, chin, and jaw. The greater petrosal nerve provides parasympathetic innervation to the sinus mucosa.

18. Which of the following drains into the middle meatus of the nasal cavity? a. Nasolacrimal duct b. Frontal, ethmoidal, and maxillary sinuses c. Ethmoidal and sphenoidal sinuses d. Sphenoidal sinus only e. Maxillary sinus only

b: The frontal sinus, the maxillary sinus, and part of the ethmoidal sinus drain into the middle meatus.

55. The greater palatine foramen is usually located: a. Distal to the third molar area. b. Between the second and third molars. c. Between the first and second molars.

b: The greater palatine foramen is located between the second and third molars. Bilateral symmetry usually exists between the sides of the skull. Many studies have reported mean distances from the greater palatine foramen to the midsagittal suture or to the posterior palatal border, but these numbers might still be inaccurate for a particular patient because of variation in the location of the greater palatine foramen. Examining a CT scan of the patient will render a definitive location of the foramen before surgery for the purpose of anesthesia or flap reflection in this region.

19. Intubation during any surgery requiring general anesthesia is necessary because, due to muscle relaxants and other drugs administered during the procedure, the patient is unable to fully relax the vocal folds. Paralysis of which muscles prevents the relaxation of the vocal folds? a. Thyroarytenoid muscles b. Posterior cricoarytenoid muscles c. Transverse arytenoid muscles d. Lateral arytenoid muscle

b: The only muscles that relax the vocal folds are the posterior cricoarytenoid muscles. The other three muscles listed here close the vocal folds. Note that there are also other effects of anesthesia that necessitate intubation.

12. When performing an emergency airway, where is the most superior site to perform this procedure so that the airway is secured below the vocal folds? a. Between the hyoid bone and the thyroid cartilage b. Between the thyroid cartilage and the cricoid cartilage c. Between the thyroid cartilage and the arytenoid cartilage

b: The quickest access to secure an airway is by incising the cricothyroid membrane. This procedure is called an emergency tracheotomy (or cricothyrotomy)

44. All of the following are true of the uncinate process EXCEPT that: a. It is crescent-shaped. b. It forms the lateral boundary of the maxillary sinus drainage pathway. c. It comes off the lateral wall of the nose at a 30-degree angle. d. It acts as a bony baffle, protecting the natural ostium of the maxillary sinus.

b: The uncinate process is an extension of the ethmoid bone that projects posteriorly from the lateral wall of the nose at about a 30-degree angle. It acts as a baffle, protecting the natural ostium of the maxillary sinus. It also forms the medial boundary of the ethmoid infundibulum, a bony groove into which the natural ostium of the maxillary sinus drains.

46. Sinus membrane elevation has the following effect on the function of the cilia found on the floor of the maxillary sinus: a. No effect b. Transient dysfunction c. Mild permanent dysfunction d. Severe permanent dysfunction

b: Timmenga et al performed endoscopically guided biopsies of the floor of the maxillary sinus before, 3 months after, and 9 months after sinus elevation and found only transient ciliary dysfunction.

35. Which of the following is true of bony septa arising from the floor of the maxillary sinus? a. They are rare, occurring in less than 10% of patients. b. They are only found in the middle third of the sinus floor. c. Most septa are tallest at their medial and lateral extents. d. Most septa run from anterior to posterior.

c: As described by Underwood in 1910, bony septa arising from the floor of the maxillary sinus are relatively common, occurring in about one-third of patients. The most common orientation is from medial to lateral, with the tallest portions at the medial and lateral extents, like an inverted flying buttress. While they are most commonly located in the middle third of the sinus, they can be found in the anterior and posterior portions as well and may assume a multitude of orientations

1. Which bone of the skull contains the optic foramen, foramen ovale, and foramen spinosum? a. Frontal b. Temporal c. Sphenoid d. Ethmoid

c: Foramina of the sphenoid include the optic foramen, foramen ovale, foramen rotundum, foramen spinosum, and superior orbital fissure.

67. Why is it important not to perforate the lingual plate of the posterior mandible during implant surgeries? a. Possible nerve trauma b. Possible muscle trauma c. Possible arterial trauma

c: It is important not to perforate the lingual plate of the posterior mandible during implant surgeries because the floor of the mouth is a highly vascularized region. Perforation of the lingual cortical plate of the posterior mandible in the region of the submandibular fossa by instrumentation or a drill may cause an arterial trauma resulting in a hemorrhage that may commence immediately or with some delay after the vascular insult. The progressively expanding lingual, sublingual, submandibular, and submental hematomas have the tendency of displacing the tongue and the floor of the mouth to obstruct the airway. This possibility is a rare but potentially fatal complication of implant surgery. To avoid this possibility, detailed knowledge of the regional arterial anatomy is imperative for the implant surgeon

43. The cilia of the sinus membrane sweep the mucus toward the natural ostium of the maxillary sinus in a consistent pattern of drainage originating where? a. The posterior wall of the maxillary sinus b. The lateral wall of the maxillary sinus c. The floor of the maxillary sinus d. The medial wall of the maxillary sinus

c: Mucus is swept across the surface of the sinus membrane at a rate of 3 to 25 mm/minute, originating from the floor of the sinus and extending in a radial pattern toward the natural ostium high on the medial maxillary wall.

7. Which muscle of mastication inserts into the apex and medial surface of the coronoid process of the mandible? a. Medial pterygoid muscle b. Lateral pterygoid muscle c. Temporalis muscle d. Masseter muscle e. Buccinator muscle

c: Temporalis muscle

42. The volume of an average adult maxillary sinus is about: a. 5-10 mL b. 10-15 mL c. 15-20 mL d. 20-25 mL

c: The adult maxillary sinus cavity is usually the largest of the paranasal sinuses by volume, typically about 15 to 20 mL. It is roughly a laterally directed pyramid in shape, with average dimensions of 3.75 cm high by 2.5 cm deep by 3 cm wide

77. After undergoing implant surgery in the anterior mandible, the patient developed hematoma in the sublingual region. This is usually the result of: a. Damage to the submental artery. b. Damage to the lingual artery. c. Damage to the sublingual artery. d. Damage to the mylohyoid artery.

c: The inferior alveolar arteries supply the symphysis of the mandible by the incisive arteries; however, an additional blood supply to the intercanine area is derived from the alveolar branches of the sublingual artery through the accessory lingual mandibular foramina. This complementary blood supply is especially important in edentulous mandibles, because arteriosclerotic changes of the inferior alveolar artery after tooth loss make the blood circulation in the mandible increasingly dependent on the external blood supply provided by the periosteum and the accessory lingual canals. This fact should be taken into consideration when performing extensive reflection of lingual mucoperiosteal flaps or when drilling close to the midline of the mandible. Disruption in the blood supply to the anterior mandible can cause hematoma in the sublingual region; several of the arteries associated with accessory lingual mandibular foramina are of sufficient size to be implicated in severe hemorrhaging episodes during implant placement in the mandibular anterior region.

4. Which nerve would most likely be affected by a mandibular fracture? a. Lingual nerve b. Hypoglossal nerve c. Inferior alveolar nerve d. Chorda tympani nerve

c: The inferior alveolar nerve courses within the mandibular canal and would therefore be injured by a mandibular fracture.

33. The sinus membrane is composed of which type of lining? a. Stratified squamous epithelium b. Simple columnar epithelium c. Pseudostratified ciliated columnar epithelium d. Stratified columnar epithelium

c: The lining of much of the nose and paranasal sinuses (including the maxillary sinus) is composed of respiratory epithelium, or pseudostratified ciliated columnar epithelium. Healthy sinus lining is 0.2 to 0.8 mm thick, includes goblet cells, and features a thick lamina propria and a relatively thin basement membrane

39. The lateral wall of the adult maxillary sinus is formed by the: a. Orbital floor b. Ethmoid bone c. Zygoma d. Alveolar portion of the maxilla

c: The zygoma forms the lateral wall of the maxillary sinus. The alveolar portion of the maxilla forms the floor of the sinus, while the orbital floor doubles as the roof of the sinus.

78. When harvesting a bone block from the chin of a dentate patient, what is the minimum recommended clearance between the superior cut and the apices of the mandibular anterior teeth? a. 3 mm b. 4 mm c. 5 mm d. 6 mm

c: To avoid damage to the anterior teeth and prevent disruption to their innervation, the minimum recommended clearance between the superior cut and the apices of the anterior mandibular teeth is 5 mm.

64. Cutting the lingual nerve will: a. Anesthetize the tongue. b. Decrease salivary flow from the submandibular gland. c. Affect the patient's sense of taste. d. All of the above e. None of the above

d: All of the above

14. The vagus nerve (CN X): a. Leaves the skull through the carotid foramen. b. Innervates the carotid sinus. c. Is transmitted through the superior orbital fissure. d. Innervates all of the muscles of the soft palate. e. None of the above

e: The vagus nerve leaves the skull through the jugular foramen with the glossopharyngeal and spinal accessory nerves.

58. Functions of the buccal fat pad include: a. Enhancing the sucking capabilities of the buccinator muscle. b. Filling the deep tissue spaces to act as gliding pads when masticatory and mimetic muscles contract. c. Cushioning important structures from the extrusion of muscle contraction or outer force impulsion. d. All of the above

d: At birth, the sucking muscles of the lips, orbicularis oris, and cheeks, principally the buccinator, are relatively better developed than the muscles of mastication. In well-nourished babies, the fat pad pushes the buccinator inward and forms a prominent elevation on the external surface of the face. It is believed by some that the sucking capabilities of the buccinator muscle are enhanced by the fat pad, which may prevent collapse of the cheeks during suction by counteracting negative pressure. The buccal fat pad also functions to fill the deep tissue spaces, acting as gliding pads when masticatory and mimetic muscles contract; as such, it represents a specialized type of fat also known as syssarcosis, or fat that enhances intermuscular motion. In addition, the buccal fat pad cushions important structures from the extrusion of muscle contraction or outer force impulsion (external trauma that may injure the facial neurovascular bundle)

41. Which of the following is NOT true of Haller cells? a. They are also known as infraorbital ethmoid cells. b. They pneumatize along the orbit from the anterior ethmoidal sinuses. c. They may narrow the maxillary sinus ostium and contribute to obstruction. d. They should always be surgically removed when noted.

d: Ethmoid cells that extend along the orbit into the drainage pathway of the maxillary sinus are called Haller cells, or infraorbital ethmoid cells. While these may contribute to obstruction or narrowing of the maxillary sinus drainage pathway, they generally do not cause symptoms.

50. During the evaluation phase for implants, a patient's cone beam computed tomography (CBCT) scan reveals an abnormality of the right maxillary sinus. The patient denies any history of sinus symptoms. Which of the following is the best course of action? a. Refer immediately to an ear, nose, and throat specialist (ENT); this appears to be a malignancy. b. Treat with amoxicillin; this is acute sinusitis. c. Tell the patient that he or she is not a candidate for implants due to incompatible anatomy. d. Refer to ENT for clearance, then proceed with implant surgery.

d: Maxillary sinus hypoplasia occurs in a small percentage of patients and is frequently asymptomatic. Referral to ENT for nasal endoscopy may detect chronic mucus drainage from the sinus, which may be correctable. There is no contraindication to implant surgery

68. Which blood vessel will be injured if the submandibular fossa is perforated during implant osteotomy preparation with a drill? a. Facial artery or one of its branches b. Lingual artery or one of its branches c. Maxillary artery or one of its branches d. a and b e. b and c f. All of the above

d: The anatomy of the lingual aspect of the mandible cannot be observed on the panoramic radiograph, nor can it be visualized because the mylohyoid muscle is located above it. Palpation can help during evaluation of the lingual aspect anatomy; however, a CT scan is best for revealing the shape of the mandible on its lingual aspect.

57. The buccal fat pad is confined in the masticatory space between: a. The masseter muscle and the medial pterygoid muscle. b. The masseter muscle and the lateral pterygoid muscle. c. The masseter muscle and the temporalis muscle. d. The masseter muscle and the buccinator muscle

d: The buccal fat pad is confined in the masticatory space between the masseter muscle laterally and the buccinator muscle (and sometimes the periosteum of the posterior wall of the maxilla) medially, with its main body resting on the buccopharyngeal fascia, which covers the external surface of the buccinator. Its anterior border goes beyond the anterior wall of the masseter and posterior to the site where the parotid duct pierces the buccinator; thus, it is covered externally in this area by the parotid duct, the zygomaticus major, the zygomaticus minor, and the superficial fascia of the face. The posterior limit is the retromolar area of the mandible. The buccal fat pad is wrapped within a thin fascial envelope.

48. Which of the following is contained within the space indicated by the white arrow? a. V1 b. Posterior superior alveolar artery c. V3 d. Infraorbital artery

d: The infraorbital canal contains the infraorbital nerve (part of V2, the trigeminal nerve) and the infraorbital artery. The infraorbital artery is a branch of the maxillary artery. It runs through the infraorbital canal and emerges onto the face through the infraorbital foramen, where branches anastomose with the angular artery and posterior superior alveolar artery, among others.

54. After bone grafting surgery in the anterior maxilla, the patient complained about continued numbness (paresthesia) in the upper lip. What nerve might have been damaged during the procedure? a. Inferior alveolar nerve b. Zygomatic nerve c. Anterior superior alveolar nerve d. Infraorbital nerve

d: The infraorbital nerve enters the orbit through the inferior orbital fissure (after branching off into the posterior superior alveolar nerves to the molars and the medial superior alveolar nerves); it traverses the infraorbital groove and canal in the floor of the orbit (where it branches off into the anterior superior alveolar nerve) and appears upon the face at the infraorbital foramen. Here it is referred to as the infraorbital nerve, a terminal branch. At its termination, the nerve lies beneath the quadratus labii superioris and divides into a leash of branches that spread out on the side of the nose, the lower eyelid (inferior palpebral nerve), and the upper lip (the superior labial nerve), joining with filaments of the facial nerve

Periods of expansion of the maxillary sinus cavity correspond to each of the following events EXCEPT: a. Eruption of the third molars b. Eruption of permanent teeth c. Extraction or loss of maxillary molars d. Episodes of acute sinusitis

d: The maxillary sinus cavity expands in size throughout childhood, with periods of more rapid expansion corresponding to dental events including eruption of the primary and permanent teeth, eruption of the third molars, and extraction or loss of maxillary molars.

21. All of the following bones form a part of the medial nasal wall EXCEPT the: a. Ethmoid b. Maxilla c. Palatine d. Inferior concha e. Vomer

d: The medial wall of the nasal cavity is formed by both bony elements and cartilage. Posteriorly, the perpendicular plate of the ethmoid bone forms the superior septum, and the vomer forms the inferior septum. Further posteriorly, the crest of both the maxilla and the palatine bone completes the posterior septum. The anterior septum is formed entirely of the quadrangular cartilage, which divides the cavity in the midline. The nasal septum can be deviated in some individuals and is a sign of nasal trauma or abnormal growth

51. The nasal septum receives its blood supply from which of the following vessels? a. Anterior ethmoidal artery b. Sphenopalatine artery c. Greater palatine artery d. All of the above

d: The nasal septum has tremendous vascular supply, with contributions from the sphenopalatine, greater palatine, and superior labial arteries (from the external carotid circulation) and the anterior and posterior ethmoidal arteries (from the internal carotid circulation). Together these form a highly vascular area on the anterior nasal septal mucosa called Kiesselbach's plexus, the site of origin of about 95% of nosebleeds.

26. Which of the following arteries is a branch of the internal carotid artery? a. Posterior cerebral artery b. Occipital artery c. Labyrinthine artery d. Ophthalmic artery e. Middle meningeal artery

d: The ophthalmic artery is the first major branch of the internal carotid artery in the anterior cranial fossa.

34. Which of the following is NOT true of the posterior superior alveolar artery? a. On average, it is found about 11.25 mm above the maxillary crest. b. It forms an anastomotic loop with the infraorbital artery. c. It originates from the internal maxillary artery. d. It is more extraosseous posteriorly and more intraosseous anteriorly.

d: The posterior superior alveolar artery originates from the internal maxillary artery, a branch of the external carotid artery. It forms an anastomotic loop with the infraorbital artery. It tends to become more extraosseous as it extends anteriorly, often being found within the elevated membrane during a lateral window approach.

30. The roots of which maxillary teeth are closest in proximity to the maxillary sinus cavity? a. Incisors b. Canines c. Premolars d. Second molars

d: The roots of the maxillary incisors and canines are not typically in close proximity to the sinus cavity. The roots of the maxillary premolars and molars, however, are consistently just inferior to the maxillary sinus floor, with the roots of the second molars nearest the sinus cavity, followed by those of the first and third molars.

15. The soft palate receives innervation from the: a. Oculomotor nerve (CN III) b. Trochlear nerve (CN IV) c. Abducent nerve (CN VI) d. Vagus nerve (CN X) and the mandibular division of the trigeminal nerve

d: The vagus nerve innervates all of the muscles of the soft palate except the tensor veli palatini, which is supplied by the mandibular division of the trigeminal nerve.

82. The primary vein(s) for venipuncture in the forearm are the: a. Cephalic vein b. Basilic vein c. Median vein d. a and b only e. All of the above

d: a and b only

2. The internal jugular vein: a. Is located in the carotid sheath. b. Receives venous drainage from the brain. c. Is a tributary of the brachiocephalic vein. d. Receives blood from the facial vein. e. All of the above

e. All of the above

8. Which muscle of mastication inserts into the angle of the mouth and orbicularis oris? a. Medial pterygoid muscle b. Lateral pterygoid muscle c. Temporalis muscle d. Masseter muscle e. Buccinator muscle

e. Buccinator muscle

23. The action of the superior part of the temporalis muscle is to: a. Elevate the mandible. b. Tense the soft palate. c. Elevate the soft palate. d. Elevate the hyoid bone. e. Retract the mandible.

e: Retract the mandible

81. The primary vein(s) for venipuncture in the antecubital fossa are the: a. Cephalic vein b. Basilic vein c. Median vein d. a and b only e. All of the above

e: The cephalic vein, basilic vein, and median vein (which divides into the median basilic and median cephalic) are all primary veins in the antecubital fossa for venipuncture. The median basilic vein is the largest and most common for phlebotomy

60. The incisive/nasopalatine canal contains the: a. Nasopalatine nerve b. Anterior branch of the greater palatine artery c. Sphenopalatine artery d. Palatine artery e. a and b f. a, b, and d g. All of the above

e: The incisive canal contains the nasopalatine nerve and the anterior branch of the greater palatine artery. There are at least two bundles in the canal because the nerves and the arteries in the canal originate from a bilateral source. The nasopalatine nerve is a branch of the posterior superior nasal nerves that arise from the pterygopalatine ganglionic branches of the maxillary nerve. It runs downward and forward to the incisive foramen, through which it passes to supply the anterior part of the palate and communicate in this area with the greater palatine nerve. Therefore, anesthesia for surgeries involving the anterior maxilla, maxillary central incisors, nasal septum, or the nasal floor can be achieved by injection into the incisive foramen. The greater palatine artery emerges from its canal through the greater palatine foramen and runs across the hard palate to the incisive foramen, through which it enters the nasal cavity and anastomoses with the sphenopalatine artery on the nasal septum and sometimes in the canal itself.

16. To inject anesthetic into the pterygopalatine fossa through a lateral approach, the needle passes through the mandibular notch of the mandible, traverses the infratemporal fossa, and enters the pterygomaxillary fissure. Which of the following structures would be at risk during the procedure? a. Maxillary artery b. Mandibular division of the trigeminal nerve (CN III) c. Pterygoid venous plexus d. Otic ganglion e. All of the above

e: The infratemporal fossa contains the maxillary artery and many of its branches, the mandibular nerve, the pterygoid plexus, and the otic ganglion, as well as the medial and lateral pterygoid muscles.