Head and Neck Congenital 01-10, 18 Flashcards
A 6-month-old infant is brought to the office because of abnormal head tilt and limited range of motion of the neck. Physical examination shows a 3-cm firm mass on the right side of the neck above the clavicle. Which of the following physical findings is most likely associated with this condition?
A) Flexion of the head toward the left shoulder
B) Flexion of the neck toward the left shoulder
C) Limited lateral flexion toward the left shoulder
D) Limited lateral flexion toward the right shoulder
E) Rotation of the head to the right shoulder
The correct response is Option C.
Torticollis is a congenital neck deformity involving shortening of the sternocleidomastoid muscle. The symptoms are head tilt and limited range of motion in the neck, and there is usually a firm mass in the body of the sternocleidomastoid muscle. The majority of the symptoms resolve in the first year of life. Occasionally, large portions of the muscle may become fibrotic, necessitating surgical release.
On physical examination, findings include flexion of the head and neck toward the ipsilateral shoulder, rotation of the head and neck to the contralateral shoulder, and a lack of lateral flexion toward the contralateral shoulder. In the case of right-sided torticollis, the findings would be:
Flexion of the head and neck toward the right shoulder
Rotation of the head and neck toward the left shoulder
Limited lateral flexion toward the left shoulder
A 45-year-old man comes to the office for follow-up examination 3 months after undergoing surgical repair of a through-and-through laceration of the left cheek. During the procedure, an injury to the parotid duct was noted and repaired. He says he feels fine, but he now has difficulty playing the trumpet because he is unable to create sufficient air pressure in his mouth. Which of the following muscles was most likely also severed?
A ) Buccinator
B ) Levator labii superioris
C ) Masseter
D ) Risorius
E ) Zygomaticus major
The correct response is Option A.
The buccinator muscle is the only muscle of facial expression that compresses the cheeks, which is an essential function for playing air-based instruments such as the trumpet. Both the buccinator and the orbicularis oris compress the lips, also necessary for playing trumpets. The buccinator muscle ordinarily contributes to the function of forming a food bolus during mastication. The path of the parotid duct typically leaves the parotid gland from its anterior border and courses superficially to the masseter muscle toward the mid cheek and then pierces the substance of the buccinator muscle, reaching the mucosa of the oral cavity opposite the maxillary second molar.
The levator labii superioris, the risorius, and the zygomaticus major muscles all have a function that contributes to separating the lips, which releases the pressure from inside the mouth. These muscles arise from bone and fascia and attach to the lips. The masseter, which originates in the zygomatic arch and inserts on the lateral surface of the ramus, elevates the mandible. The masseter has no role in holding intrabuccal or lip pressure.
A 20-year-old man comes to the office because he has had paraesthesia of the anterior lateral aspect of the tongue since undergoing removal of the mandibular third molars 3 weeks ago. The most likely cause is injury to which of the following nervous structures?
A ) Chorda tympani
B ) Facial
C ) Glossopharyngeal
D ) Hypoglossal
E ) Lingual
The correct response is Option E.
General sensation of the anterior two thirds of the tongue is supplied by the lingual nerve, which is a branch of the mandibular division of the trigeminal. Taste in the anterior two thirds of the tongue is supplied by the chorda tympani from the facial nerve. The chorda tympani joins the lingual nerve and runs anteriorly in its sheath. The glossopharyngeal nerve supplies the mucosa of the posterior one third of the tongue. The hypoglossal nerve is the motor nerve to the tongue, and the facial nerve is the motor nerve to the face.
A 26-year-old woman is being evaluated because she has had complete left-sided, flaccid facial paralysis since she awoke 3 hours ago. She also has a metallic taste in her mouth and hypersensitivity to sound. Denervation of which of the following muscles is the most likely cause of the hypersensitivity to sound?
A ) Levator palatini
B ) Stapedius
C ) Tensor tympani
D ) Tensor veli palatini
E ) Zygomaticus major
The correct response is Option B.
The 26-year-old woman described has the typical history of Bell palsy. In patients with Bell palsy, the entire nerve is inflamed, but the maximum conduction block is either in the meatal or labyrinthine segments. Because the conduction block is proximal to the chorda tympani and stapedial nerve, patients also experience a change in taste and a decreased ability to accommodate (ie, dampen) loud noises.
When an acoustic tumor causes facial paralysis, the paralysis is usually slowly progressive. Patients generally present with a hearing loss, not a hypersensitivity to noise.
The tensor tympani muscle attaches to the malleus and is innervated by the trigeminal nerve, not the facial nerve. The tensor veli palatini muscle is also innervated by the trigeminal nerve and is responsible for active dilatation of the eustachian tube. Blockage of the eustachian tube would cause a hearing loss.
The zygomaticus major muscle is innervated by the facial nerve. Denervation causes a decreased ability to smile, not hearing loss. The levator palatini muscle is innervated by the vagus nerve.
A 58-year-old man comes to the office for consultation regarding treatment 3 weeks after receiving a diagnosis of squamous cell cancer of the soft palate. He says he has had pain in the left ear for the past 2 months. Examination of the ear shows no abnormalities. The most likely cause of the pain is involvement of which of the following nerves?
A ) Auricular branch of the vagus (X)
B ) Auriculotemporal
C ) Great auricular
D ) Superficial temporal
E ) Vestibulocochlear (VIII)
The correct response is Option A.
The auricular branch of the vagus nerve (Arnold nerve) carries sensory input from the ipsilateral concha and oropharynx. Chronic external ear pain may alert the astute physician of more serious intraoral pathology. The auriculotemporal nerve carries sensory information from the anterior and superior external auditory canal, and the great auricular nerve relays sensation from the lower half of the ear. The lesser occipital nerve provides sensory input from the superior cranial surface of the ear. Although the superficial temporal nerve is not an anatomically recognized structure, the superficial temporal artery supplies vascular inflow to the anterior external ear.
A 45-year-old woman comes to the office because she has had a 4-week history of a rapidly enlarging left parotid mass. On physical examination, the patient has ptosis of the left eyebrow and is unable to fully close the left eye or depress the left lower lip. The most likely cause of these findings is tumor involvement at which of the following foramina at the base of the skull?
A ) Jugular
B ) Lacerum
C ) Ovale
D ) Rotundum
E ) Stylomastoid
The correct response is Option E.
A history of a progressive facial paralysis associated with a parotid mass suggests the diagnosis of a malignant parotid tumor. The temporal, zygomatic/buccal, and ramus mandibularis branches are affected, indicating that the main trunk of the facial nerve is invaded by tumor. The facial nerve exits the skull base from the stylomastoid foramen. The foramen lacerum, foramen ovale, and the foramen rotundum contain the internal carotid artery, mandibular (V3) nerve, and maxillary (V2) nerve, respectively. The glossopharyngeal (IX), vagus (X), and spinal accessory (XI) nerves emerge from the jugular foramen.
A 5-year-old boy is brought to the office because of a 10-day history of inflammation of a midline neck mass that his parents first noticed 1 year ago. Physical examination shows a 35-mm mass just inferior to the hyoid bone. Which of the following is the most likely diagnosis?
A ) Branchial cleft remnant
B ) Lingual thyroid gland
C ) Mucoepidermoid carcinoma
D ) Reactive lymph node
E ) Thyroglossal duct cyst
The correct response is Option E.
The patient described has a thyroglossal duct cyst. Thyroglossal duct cysts can form anywhere along the thyroglossal duct, which extends from the foramen cecum of the tongue to the final position of the thyroid gland in the neck, below the laryngeal cartilage. Normally, the thyroglossal duct atrophies and disappears. However, a remnant of it may persist and form a cyst in the tongue or anterior midline of the neck, most commonly inferior to the hyoid bone. Thyroglossal duct cysts are often asymptomatic unless they become infected, as this one has.
Reactive lymph nodes are the most common neck mass in children. They are usually found laterally in the submandibular and jugulodigastric areas. Branchial cleft remnants (sinuses and cysts) arise from the branchial apparatus. They are also located laterally, along the anterior border of the sternocleidomastoid muscle, usually just inferior to the angle of the mandible. Lingual thyroid glands are a type of ectopic thyroid located within the tongue. Ectopic thyroid glands can be located along the course of the thyroglossal duct and are a result of failure of the thyroid to descend. Unlike thyroglossal duct cysts, they represent the only thyroid tissue present in the patient. Mucoepidermoid carcinomas are salivary gland malignancies found in children, and they most commonly appear within the parotid gland.
A 4-year-old child has a congenital sinus tract opening at the anterior border of the lower third of the sternocleidomastoid muscle. Which of the following nerves is most likely to be injured during surgical excision of the fistulous tract?
A ) Accessory (XI)
B ) Facial (VII)
C ) Hypoglossal (XII)
D ) Lingual
E ) Vagus (X)
The correct response is Option C.
The child described has a branchial cleft sinus or fistula, which is an embryologic remnant of the cleft between the second and third branchial arches. The fistulas can be bilateral in up to 30% of cases. Histologically, they are lined with stratified squamous epithelium but may also have some pseudostratified columnar ciliated epithelium in their walls. They also contain keratin, hair follicles, sweat glands, and sebaceous glands. They must be completely excised to prevent recurrence.
The second branchial arch descends over the third, resulting in an external opening in the lower neck. The internal opening lies at the anterior aspect of the posterior pillar of the fauces, just behind the tonsil (which is the junction between the second and third branchial arches). Usually, the fistula will follow the carotid sheath upwards before crossing the hypoglossal (XII) nerve and passing between the internal and external carotid arteries to reach the tonsillar fossa. As a result, the hypoglossal nerve is at risk during surgery. The facial (VII) nerve is not in the vicinity of the fistula. The facial nerve is intimately related to first branchial arch sinuses and cysts. The spinal accessory (XI) nerve is in the posterior triangle of the neck and is not in the vicinity of the surgical field to remove this type of fistula. The lingual nerve lies at a higher level and is safe. The left recurrent laryngeal nerve arises from the vagus (X) nerve low in the neck before hooking around the subclavian artery and passing medially behind the common carotid artery to reach the groove between the trachea and the esophagus. As a result of this anatomy, it too is out of harm €™s way. The vagus (X) nerve lies in the carotid sheath behind, and somewhat between, the internal jugular vein and the common carotid artery. The fistula lies on the other side of the great vessels. At the carotid bifurcation, the vagus nerve is lateral to the fistulous tract and stands less chance of injury than does the hypoglossal nerve.
A 20-year-old man comes to the emergency department because of a deep laceration of the lower lip. Bilateral mental nerve blocks will be used to anesthetize the lip properly prior to repair. Which of the following is the most appropriate landmark for needle placement for the blocks?
A ) Mandibular second premolar
B ) Maxillary canine
C ) Oral commissure
D ) Retromolar fossa
E ) Sigmoid notch
The correct response is Option A.
The inferior alveolar nerve enters the mandible on the medial side of the ramus about 10 mm below the sigmoid notch. It then courses through the canal closest to the buccal cortical plate in the region of the ramus, angle, and down to the third molar with an average distance of 1.8 mm ± 1 mm. The nerve then swerves away at a position of 4.1 mm + 1 mm from the buccal cortex as it passes the region of the first and second molars. As it traverses the mandibular body, it is lowest and closest to the inferior cortex (7.5 + 1.5 mm) near its exit site at the level of the first molar and second premolar via the mental foramen on the anterior surface of the mandible. The mental nerve supplies the skin of the lower lip and chin right up to the midline.
The maxillary canine may be used as a landmark for needle insertion toward the infraorbital foramen during infiltration of the infraorbital nerve. The maxillary second molar is a landmark typically used to locate the opening of the Stensen duct.
The oral commissure is used for facial aesthetic measurements and not for nerve blocks.
The retromolar fossa, posterior to the mandibular third molar, is the preferred location for needle insertion to anesthetize the buccal nerve, which normally supplies sensibility to the central cheek.
The sigmoid notch is used as a landmark to reference the location of the inferior alveolar nerve.
In the temporal region, the frontal branch of the facial nerve is located within which of the following layers?
A ) Subcutaneous tissue
B ) Superficial temporal fascia
C ) Superficial layer of the deep temporal fascia
D ) Superficial temporal fat pad
E ) Deep layer of the deep temporal fascia
The correct response is Option B.
As depicted in the image shown, the temporal or frontal branch of the facial nerve is found within the superficial temporal or temporoparietal fascia. In the temporal region, the facial nerve can be injured with a coronal approach. The layers from superficial to deep in this region include: (1) skin, (2) subcutaneous tissue, (3) superficial temporal fascia also known as the temporoparietal fascia, (4) superficial layer of the deep temporal fascia, (5) superficial temporal fat pad, (6) deep layer of the deep temporal fascia, (7) temporalis muscle.
When the coronal flap is raised, as soon as the yellow superficial temporal fat pad is seen beneath the superficial layer of the deep temporal fascia, the superficial layer of the deep temporal fascia must be incised and included with the coronal flap to protect the frontal branch, which is in the superficial temporal fascia (temporoparietal fascia), one layer superficial to this.
The optic nerve passes through which of the following bones of the orbit?
A ) Ethmoid
B ) Frontal
C ) Lacrimal
D ) Maxilla
E ) Sphenoid
The correct response is Option E.
Seven bones make up the orbit: the frontal bone, maxilla, zygoma, ethmoid, lacrimal, greater and lesser wings of the sphenoid, and the palatine bone. The frontal, maxilla, zygoma, and ethmoid bones constitute the strong outer rim of the orbit and protect the more delicate bones in the interior orbit. The lesser wing of the sphenoid forms the posterior aspect of the roof of the orbit and transmits the optic nerve and ophthalmic artery through the optic canal. The greater wing of the sphenoid contains the superior orbital fissure, which transmits the lacrimal nerve, frontal nerve, trochlear nerve, superior and inferior branches of the oculomotor nerve, the nasociliary nerve, and the abducens nerve.
The levator veli palatini muscle is innervated by which of the following nerves?
A ) Facial (VII)
B ) Hypoglossal (XII)
C ) Mandibular branch of the trigeminal (V)
D ) Maxillary branch of the trigeminal (V)
E ) Vagus (X)
The correct response is Option E.
The levator veli palatini (levator muscle) is a muscular sling in the posterior palate that is critical for palatal closure. Embryologically, the muscle arises from the fourth pharyngeal arch and, as a result, is innervated by the pharyngeal plexus, a derivative of the vagus (X) nerve. The two portions of the levator muscle arise from the eustachian tube and sphenoid bone while inserting into the other levator muscle in the midline of the soft palate. The function of the levator muscle is to elevate and posteriorly reposition the soft palate against the posterior nasal wall to assist in speech. This closes the velopharyngeal port while opening the eustachian tubes. The vagus also innervates several other muscles involved in normal speech development: the palatoglossus, the pharyngeal constrictors, the musculus uvulae, and the palatopharyngeus. The palatoglossus muscles form the anterior tonsillar pillars and lift the base of the tongue. The musculus uvulae originate from the palatine aponeurosis and the posterior nasal spine and insert into the uvula. With speech, these muscles will contract, causing a bulging of the soft palate and subsequent velopharyngeal closure. The uvula is lifted and bent backward.
The facial (VII) nerve innervates the muscles of facial animation, including the buccinator.
The hypoglossal (XII) nerve provides motor function to the tongue.
The trigeminal (V) nerve has three individual branches. The first branch, the ophthalmic division, is strictly a sensory branch. The second, or maxillary, division is also sensory. The third branch, the mandibular division, is the largest branch and is a mixed sensory and motor branch. Embryologically, the mandibular division arises from the first branchial (or mandibular) arch and provides motor function to the muscles arising from this arch. These muscles include the temporal, masseter, pterygoids, mylohyoid, tensor tympani, and the anterior belly of the digastric. It also innervates the tensor veli palatini. This muscle arises from the eustachian tube and medial pterygoid plate, wraps around the hamulus, and then inserts into the midline of the soft palate. During swallowing, these muscles tense the soft palate, opening the eustachian tube and allowing the tongue to move food posteriorly.
A 35-year-old man is brought to the emergency department following a motorcycle collision. Examination shows swelling and deformity of the mandible. Radiographs show a left subcondylar fracture with the proximal fragment displaced forward. Which of the following muscles is most likely involved in the displacement?
A ) Digastric
B ) Lateral pterygoid
C ) Masseter
D ) Medial pterygoid
E ) Temporalis
The correct response is Option B.
The origin of the lateral pterygoid muscle (shown below) has two components: one that attaches to the temporomandibular joint capsule and disc, and one that attaches to the fovea in the neck of the mandible. Proximally (anteriorly), the superior head attaches to the greater wing of the sphenoid bone, and the inferior head to the lateral surface of the lateral pterygoid plate. Therefore, in a subcondylar fracture, the lateral pterygoid muscle is in position to draw the proximal fragment forward.
The digastric muscle extends from the mastoid process of the temporal bone to the hyoid bone and to the anterior mandible. It depresses the mandible (inferior movement) or elevates the hyoid. The masseter, medial pterygoid, and temporalis elevate the mandible from the region of the ramus, angle, or coronoid process. The masseter originates in the zygomatic arch and inserts on the lateral surface of the ramus. The medial pterygoid originates on the lateral pterygoid plate and the tuberosity of the maxilla and attaches to the medial surface of the angle of the mandible. The temporalis muscle is fan-shaped and originates from the floor of the temporal fossa and inserts in the coronoid process and anterior border of the ramus.
The nasolacrimal duct drains into the nose at which of the following anatomic locations?
A ) Inferior concha
B ) Inferior meatus
C ) Middle concha
D ) Middle meatus
E ) Superior concha
The correct response is Option B.
The nasolacrimal duct, which maintains the drainage of the nasolacrimal system, drains into the inferior meatus just below the inferior concha (see diagram). Other structures also drain into the nose. The auditory tube opens into the nasopharynx just posterior to the inferior concha. The sphenoid sinus drains into the sphenoethmoid recess superior and posterior to the superior concha. The posterior ethmoid air cells drain into the superior meatus. The nasofrontal duct,
The mylohyoid muscle is innervated via which of the following nerves?
A ) Accessory
B ) Glossopharyngeal
C ) Hypoglossal
D ) Mandibular
E ) Maxillary
The correct response is Option D.
The mylohyoid muscle is a flat, triangular muscle that with its opposite forms the muscular floor of the oral cavity. It originates from the oblique line of the mandible from the mandibular symphysis to the last molar tooth and inserts along the body of the hyoid bone in median fibrous raphe from the mandibular symphysis to the hyoid bone. The mylohyoid muscle elevates the floor of the mouth during swallowing and elevates the hyoid bone, which pushes the tongue upward during swallowing or tongue protrusion. This muscle also lowers the mandible and assists in opening the mouth, mastication, sucking, and blowing.
The primary motor innervation to the mylohyoid muscle is the mylohyoid branch of the inferior alveolar nerve of cranial nerve V (mandibular nerve). This nerve is a branch of the mandibular or third division of the trigeminal nerve. The two major nerves of the third division of the trigeminal nerve are the lingual nerve and the inferior alveolar nerve. The maxillary nerve is a branch of the second division of the trigeminal nerve and provides sensation to the ipsilateral face, side of the nose, lip, and upper teeth. The hypoglossal nerve (cranial nerve XII) provides motor innervation to the tongue. This nerve supplies all intrinsic muscles and all but one extrinsic muscle of the tongue. The exception is the palatoglossus muscle, which is supplied by cranial nerve X. The spinal accessory nerve, which is cranial nerve XI, supplies motor innervation to the sternocleidomastoid and trapezius muscles. The glossopharyngeal nerve (cranial nerve IX) is a complex nerve that supplies efferent nerve innervation to the parotid gland and carries sensations to the carotid body and carotid sinus. This nerve also provides general sensation to the posterior one third of the tongue, the skin of the external ear, and the internal surface of the tympanic membrane and supplies taste for the posterior one third of the tongue.
The 4-month-old boy shown has congenital midline neck and mandibular anomalies, including a mild clefting of the mandible and atrophic skin in the central anterior neck. These anomalies are a result of the incomplete fusion of which of the following paired branchial arches?
A ) First
B ) Second
C ) Third
D ) Fourth
E ) Fifth
The correct response is Option B.
Congenital midline cervical clefts are a result of a failure of fusion of the paired second branchial arches in the midline during embryogenesis. It is a rare anomaly of the anterior neck diagnosed on the basis of the clinical presentation at birth. The most commonly reported features are a cleft of reddened, thinned tissue in the midline, a protuberance of skin superiorly, a blind epithelium-lined sinus tract caudally, and a fibrous subcutaneous cord. The cord may limit neck movement. There is some degree of retrognathia and variable degrees of clefting of the lip and mandible. Other anomalies that have been found in association with midline cervical cleft are thyroglossal duct cysts and ectopic bronchogenic cysts.
Branchial arches begin to develop in the fourth week as neural crest cells migrate into the head and neck region. By the end of the fourth week, four pairs of branchial arches are visible externally. The fifth and sixth arches are small and not yet visible on the surface of the embryo. The branchial arches are separated by prominent clefts called branchial grooves.
A 70-year-old man is scheduled to undergo wedge resection of a lesion on the lower lip. Physical examination of the lower lip shows an ulcerated, well-circumscribed 5-mm lesion 1 cm medial to the right oral commissure. Which of the following foramina is the most appropriate site for instillation of anesthetic for the procedure?
A ) Inferior alveolar
B ) Infraorbital
C ) Mental
D ) Nasopalatine
E ) Sphenopalatine
The correct response is Option C.
The most appropriate area for block infiltration is an intraoral blockade of the mental nerve. The inferior alveolar nerve travels through the mandible entering at the medial ramal border and exits at the mental nerve at the mental foramen at the level of the first and second bicuspid teeth, 1 cm below the alveolar ridge.
Blockage of the inferior alveolar nerve foramen requires injection at its entry in the posterior mandible, or within the bony canal €”an area not easily accessible.
Numbness of the upper lip and nasal sidewall can be accomplished with blockade of the infraorbital nerve.
Nasal palatine anesthetic produces numbness of the external nose.
Sphenopalatine nerve blockade produces anesthesia in the internal nose and palate.
The muscles of mastication are derived from which of the following branchial arches?
A ) First
B ) Second
C ) Third
D ) Fourth
E ) Fifth
The correct response is Option A.
The muscles of mastication (temporalis, masseter, and medial and lateral pterygoids), the mylohyoid, and anterior belly of the digastric, and the tensors veli palatini and tympani are derived from the first branchial arch.
Arch Nerve
First- Mandibular Trigeminal, V2, V3
Second- Hyoid Facial (VII)
Third Glossopharyngeal (IX)
Fourth and Sixth Superior laryngeal branch of vagus (X) Recurrent laryngeal branch of vagus (X)
Muscles
Muscles of mastication Mylohyoid and anterior belly of digastric Tensor tympani Tensor veli palatini
Muscles of facial expression Stapedius Stylohyoid Posterior belly of digastric
Stylopharyngeus
Cricothyroid Levator veli palatini Constrictors of pharynx Intrinsic muscles of
larynx
A 48-year old woman comes to the office because she has had persistent epiphora since she sustained a naso-orbital-ethmoid fracture one year ago. Jones I fluorescein dye test is performed. If the results of this test are normal, in which of the following locations is the dye most likely to be found?
(A) Inferior meatus
(B) Lower canaliculus
(C) Middle meatus
(D) Nasolacrimal duct
(E) Upper canaliculus
The correct response is Option A.
Epiphora is the accumulation of tears that are not evacuated by the lacrimal drainage system. The tears will often overflow onto the cheek. Injuries to the lacrimal drainage system have been reported to occur in 5% to 21% of patients sustaining naso €‘orbito €‘ethmoid trauma. Jones I and Jones II dye testing can be used to diagnose the level of obstruction.
In a Jones I dye test, fluorescein dye is instilled into the conjunctival sac. A cotton €‘tipped applicator is placed under the inferior turbinate, the site of the inferior meatus. In a positive test, dye flows through the lacrimal system and exits at the inferior meatus. Dye is recovered on the applicator. In a negative test, no dye is recovered. This indicates an obstruction in the lacrimal drainage system.
The Jones II dye test is performed to localize the level of obstruction within the drainage system. This test is performed immediately after the Jones I test. An irrigation cannula is inserted into the punctum. Saline is irrigated through the cannula. If dye-stained fluid is obtained in the nose, the test is positive, and a partial obstruction of the lacrimal drainage system is diagnosed. If no dye is obtained in the nose, the test is negative. If dye exits the other canaliculus, the obstruction is in the lower portion of the system. If no dye returns through the other canaliculus, but dye refluxes through the same canaliculus, then the obstruction is in the upper part of the system.
An otherwise healthy 20-year-old woman comes to the office because she has had a painless lump on the left floor of the mouth for the past three weeks. The lump has increased in size during the past week. Physical examination shows a fluctuant, 2-cm blue mass that is not tender to palpation. Which of the following is the most likely diagnosis?
(A) Lingual thyroid
(B) Ranula
(C) Thyroglossal duct cyst
(D) Torus
(E) Vascular anomaly
The correct response is Option B.
A ranula is a mucocele or mucous extravasation phenomenon in the floor of the mouth, arising from the ducts of the sublingual or submandibular glands, often as a sequela of obstruction of the sublingual gland. It usually presents as a unilateral swelling of the floor of the mouth that is fluctuant and tinted blue or glossy white. Treatment includes marsupialization or surgical excision including the sublingual gland. The ranula may herniate through the muscles of the floor of the mouth and present as a €œplunging ranula € or cervical mass.
A lingual thyroid is an uncommon condition in which the embryonic thyroid gland does not descend into the neck and presents as a firm, nontender mass at the tongue base.
A thyroglossal duct cyst represents residual epithelium-lined tracts that trace the path of descent of the thyroid and can be found anywhere in the paramedial region of the neck but are usually in the midline.
A torus is an exostosis and is a slow-growing, hard mass arising from the palate or mandible. The enlargement consists of bone covered by mucosa. Excision is indicated for tori that become symptomatic or bothersome.
Vascular anomalies are present at birth and grow with the patient. It would be unusual for a vascular anomaly to initially present in an adult.
At which of the following intraosseous locations is the inferior alveolar nerve farthest from the buccal cortex?
(A) Angle
(B) First molar
(C) Ramus
(D) Second premolar
(E) Third molar
The correct response is Option B.
The inferior alveolar nerve (IAN) is closest to the lingual cortex at the level of the first and second molars. The anatomy of the IAN is relevant in orthognathic and trauma surgery. The incidence of nerve transection during sagittal split osteotomy is 3.5% and usually occurs at the level of the third molar. Osteotomy design and chisel placement are based on knowledge of the anatomy of the IAN. The IAN enters the mandible on the medial side of the ramus approximately 10 mm below the sigmoid notch. It then courses through the canal that is closest to the buccal cortical plate in the region of the ramus and angle and down to the third molar; the average distance is 1.8 ±1 mm. The nerve then swerves away at a position of 4.1 ±1 mm from the buccal cortex as it passes the region of the first and second molars. As it traverses the mandibular body, it is lowest and closest to the inferior cortex (7.5 ±1.5 mm) near its exit site at the level of the first molar and second premolar.
In the developing embryo, the stapes is formed from tissues of which of the following visceral arches?
(A) First
(B) Second
(C) Third
(D) Fourth
(E) Fifth
The correct response is Option B.
The first visceral arch ultimately forms the malleus, incus and the structures of the mandible. The second arch forms the stapes, the styloid and the facial musculature. The third arch forms the stylopharyngeus. The fourth, fifth and sixth arches contribute to the pharyngeal and laryngeal muscles as well as the thyroid cartilage.
A 45 year old man has persistent maxillary sinusitis subsequent to open reduction and internal fixation of pan €‘facial fractures and a failed course of antibiotics. Surgical enlargement of the ostium of the sinus is planned as a drainage procedure via an endoscopic approach. Direction of the endoscope into which of the following areas within the nasal cavity is most appropriate?
(A) Inferior concha
(B) Inferior meatus
(C) Middle meatus
(D) Superior concha
(E) Superior meatus
C Middle Meatus
Dermoid cysts of the nasal dorsum, anterior encephaloceles, and nasal gliomas are all thought to result from failed closure of which of the following structures?
(A) Anterior fontanelle
(B) Dorsum sellae
(C) Fonticulus frontalis
(D) Foramen rotundum
(E) Metopic suture
(C) Fonticulus frontalis
Which of the following foramina of the middle cranial fossa hosts passage of the oculomotor (III), trochlear (IV), and abducens (VI) nerves?
(A) Optic canal
(B) Ovale
(C) Rotundum
(D) Spinosum
(E) Superior orbital fissure
The correct response is Option E.
The foramen that allows passage of the oculomotor (III), trochlear (IV), and abducens (VI) cranial nerves is the superior orbital fissure, which is located at the orbital apex. This foramen also transmits the lacrimal, frontal, and nasociliary nerves; the sympathetic branches; the superior and inferior ophthalmic veins; the orbital branch of the middle meningeal artery; and the recurrent branch of the lacrimal artery. Hemorrhage or traumatic edema inside this foramen causes a unique collection of symptoms due to compression and loss of function of the traveling nerves, termed superior orbital fissure syndrome. The apex of the orbit also contains two other foramina: the optic canal, which transmits the optic (II) nerve and the ophthalmic artery, and the inferior orbital fissure, which allows passage of the infraorbital and zygomatic nerves. The foramen rotundum communicates between the middle cranial fossa and the pterygopalatine fossa. The maxillary division of the trigeminal (V) nerve is the only structure that passes through this foramen. The foramen ovale links the middle cranial fossa to the infratemporal fossa and transmits the mandibular division of the trigeminal nerve, the lesser petrosal branch of the glossopharyngeal (IX) nerve, the accessory meningeal branch of the maxillary artery, and an emissary vein. The foramen spinosum, located adjacent to the foramen ovale, also sits between the middle cranial and the infratemporal fossae. The foramen spinosum contains the meningeal branch of the mandibular division of the trigeminal nerve and the middle meningeal artery and vein.
Which of the following nerves supplies sensation to the superior anterior aspect of the helix of the ear?
(A) Arnold
(B) Auriculotemporal
(C) Great auricular
(D) Greater occipital
(E) Lesser occipital
The correct response is Option B.
Sensation to the external ear is provided by the great auricular nerve, auricular branch of cranial (X) nerve (Arnold nerve), the auriculotemporal nerve, a branch of the mandibular branch of cranial (V) nerve (trigeminal nerve), and the lesser occipital nerve. Sensation to the superior anterior aspect of the helix is provided by the auriculotemporal nerve. The Arnold nerve provides sensation to the ear canal, whereas the posterior aspect of the external ear is provided by the lesser occipital nerve and most of the inferior two thirds of the external ear is provided by the great auricular nerve. The greater occipital nerve provides sensation to the skin and the posterior aspect of the scalp.
An otherwise healthy 15-year-old boy is brought to the office by his parents because he has had painless swelling of the hard palate for the past year. A photograph of his mouth is shown. Physical examination shows a lesion that is solid, firm, fixed, noncompressible, nontender, and covered with healthy palatal mucosa. Which of the following is the most likely diagnosis?
(A) Craniofacial fibrous dysplasia
(B) Maxillary torus
(C) Skull base glioma
(D) Squamous cell carcinoma
(E) Submucous cleft palate
The correct response is Option B.
In an otherwise healthy young patient with a solid asymptomatic lesion consistent with bone on the hard palate, the most likely diagnosis is a maxillary torus or torus palatinus.
Maxillary and mandibular tori are benign osteoblastic tumors and tend to be well encapsulated, circumspect, submucosal, and expand gradually without invading adjacent structures. Torus palatinus occurs on the midline of the hard palate and requires treatment only if it becomes symptomatic or interferes with function.
Fibrous dysplasia is a benign tumor of bony origin that may present as a component of McCune-Albright syndrome (polyostotic fibrous dysplasia) or as a localized condition of the craniofacial skeleton, usually the upper facial skeleton. An isolated palatal occurrence of fibrous dysplasia would be highly unlikely.
Gliomas are believed to be encephaloceles that have lost their intracranial connections. External gliomas usually appear at or just lateral to the nasal root as reddish, firm, noncompressible, lobular lesions with cutaneous telangiectasia. The do not transilluminate or pulsate. Skull base gliomas are usually intranasal, and while potentially being associated with bony defects, would not present in this fashion.
Although squamous cell carcinoma frequently presents as an intraoral mass, it is not the most likely diagnosis in a healthy, young patient with a hard bony lesion of the palate.
Submucous cleft palates present with bifid uvulas, a bony notch or defect at the edge of the hard palate, and a zona pellucida, or thin, bluish, strip of mucosa in the midline of the soft palate secondary to diastasis of the levator muscle.
A 37-year-old man is brought to the emergency department one hour after he sustained injuries to the face in a motor vehicle collision. Physical examination shows lacerations around the bridge of the nose and mobility of the bony pyramid. Radiographs show a fracture of the nasal bones. Absence of sensation of the nasal septum and lateral nasal wall is noted. This patient has most likely sustained injuries to which of the following nerves?
(A) Anterior ethmoidal
(B) Frontal
(C) Infraorbital
(D) Infratrochlear
(E) Lacrimal
The correct response is Option A.
The ophthalmic branch or first division of the trigeminal nerve enters the orbit via the superior orbital fissure. The three sensory branches include the lacrimal, frontal, and nasociliary nerves. The nasociliary nerve courses above the optic nerve and below the superior rectus muscle. Its first branch is the posterior ethmoidal nerve, which provides sensation to the posterior ethmoid sinuses. The terminal branches of the nasociliary nerve are the anterior ethmoidal nerve and the infratrochlear nerve. The former exits via a foramen of the same name, and ultimately reaches the roof of the nose, providing sensation to the septum and lateral wall. Its terminal branch, the dorsal nasal nerve, supplies innervation to the tip.
A 45 year old man who is employed as a construction worker comes to the office because of pain in the small and ring fingers of the nondominant left hand. He says the pain worsens and the fingers become blotchy on exposure to cold. He has smoked one pack of cigarettes daily for 30 years. Examination shows subungual hemorrhages in the small finger and a digital brachial index of 0.4. Arteriography shows segmental occlusion of the ulnar artery at the wrist. Which of the following is the most appropriate management of this patient €™s condition?
(A) Administration of a calcium channel blocker
(B) Intraarterial thrombolysis/fibrinolysis
(C) Resection and reconstruction of segmental ulnar artery
(D) Smoking cessation
(E) Stellate ganglion block
The correct response is Option C.
Hypothenar hammer syndrome (HHS) describes digital ischemic symptoms secondary to either occlusion or aneurysmal dilation of the ulnar artery adjacent to the hamate. Although typically related to activities that involve repetitive trauma (eg, use of vibrating tools) to the palm, evidence exists to suggest that the condition arises in vessels with preexisting abnormalities, even in the absence of trauma.
In cases of critical digital ischemia with characteristic segmental occlusion on arteriography, optimal treatment involves resection of the diseased segment and reconstruction. Reversed vein graft represents the standard bypass conduit; however, as in coronary artery bypass grafting, arterial conduits (inferior epigastric artery) have been suggested as better matched in size and less prone to aneurysmal dilation later.
Calcium channel blockers and sympathetic blockade may alleviate vasospastic responses in the patent vessels distal to the occlusion. These interventions may be combined with surgical therapy and can be considered as primary interventions in patients with less symptomatic hands and a digital brachial index less than 0.7.
Intraarterial thrombolysis should not be used in the setting of the chronic, occlusive disease of HHS.
Smoking has been associated with HHS, but cessation alone in the setting of severe ischemia will not reverse the changes.
A 7-year-old boy is brought to the office for consultation regarding the congenital nerve palsy shown. The affected nerve is derived from which of the following branchial arches?
(A) First
(B) Second
(C) Third
(D) Fourth
(E) Fifth
The correct response is Option B.
The facial nerve (cranial nerve VII) is derived from the second branchial arch and consists primarily of motor fibers that are distributed to the muscles of facial expression. Branchial arches begin to develop in the fourth week as neural crest cells migrate into the head and neck region. By the end of the fourth week, four pairs of branchial arches are visible externally. The fifth and sixth arches are small and not visible on the surface of the embryo yet. The branchial arches are separated by prominent clefts called branchial grooves.
A 76-year-old man undergoes a radial forearm flap procedure for reconstruction of a defect of the floor of the mouth resulting from excision of carcinoma. During dissection of vessels in the neck for microsurgical anastomosis, the surgeon has difficulty visualizing an appropriate recipient artery because of high bifurcation of the carotid artery. Which of the following muscles can be cut to provide better exposure of the recipient artery?
(A) Digastric
(B) Geniohyoid
(C) Omohyoid
(D) Sternohyoid
(E) Styloglossus
The correct response is Option A.
There are only two muscles that would be in the area of a high bifurcation of the carotid that may need to be cut for better exposure: posterior belly of the digastric and the stylohyoid, which span across the skull base to the hyoid. Because the stylohyoid is not mentioned, the digastric muscle is the correct choice. The microsurgeon usually divides the digastric muscle at the level of the fibrous loop for the intermediate digastric tendon. The other muscles are never dissected or divided during this procedure.
Which of the following muscles of facial expression is innervated on its anterior surface?
(A) Depressor anguli oris
(B) Levator anguli oris
(C) Levator labii superioris
(D) Orbicularis oris
(E) Zygomaticus major
The correct response is Option B.
The muscles of facial expression receive their innervation from cranial nerve VII (facial nerve). The facial nerve innervates the muscles of facial expression along the posterior surface of the muscle in most cases. The exceptions to this rule include the levator anguli oris, the buccinator, and the mentalis muscle. At the modiolus, the fibers of the levator anguli oris coalesce with fibers of the zygomaticus major, orbicularis oris, risorius, buccinator, and depressor anguli oris. The levator anguli oris lies deep to the other muscles and receives its innervation along its anterior surface.
Formation of the primary palate begins during which of the following weeks of gestation?
(A) First
(B) Third
(C) Fifth
(D) Eighth
(E) Eleventh
The correct response is Option C.
Formation of the primary palate begins during the fifth week of gestation and is completed by the end of the sixth week of gestation. Anatomically, it is located anterior to the incisive foramen. The premaxilla only contains the central and lateral incisors.
For each structure of the neck, choose the fascial plane in which it is enveloped (A -C).
(A) Pretracheal fascia
(B) Prevertebral fascia
(C) Superficial fascia
142.
Trapezius muscle
143.
Anterior scalene muscle
The correct response for Item 142 is Option C and for Item 143 is Option B.
The superficial fascia envelops the sternocleidomastoid, the trapezius, and the suprahyoid muscles. The prevertebral fascia incorporates all of the scalene and paravertebral muscles. The pretracheal fascia incorporates the thyroid and trachea.
Which of the following muscles of the mouth is innervated by the mandibular branch of the facial (VII) nerve?
(A) Buccinator
(B) Depressor anguli oris
(C) Levator anguli oris
(D) Orbicularis oris
(E) Risorius
The correct response is Option B.
The other mimetic muscles innervated by the mandibular branch of the facial nerve include the depressor labii inferioris and the mentalis muscle. These muscles control movement of the lower lip to either pull it down and laterally or to protrude it. Paralysis of the nerve results in elevation of the angle of the mouth and of the lower lip on the affected side. This nerve is at risk for injury during rhytidectomy or neck lift procedures, parotidectomy, and neck dissection.
The buccinator, levator anguli oris, orbicularis oris, and risorius are all innervated by the buccal branch of the facial nerve. Anatomic variation may be encountered with the risorius muscle, which is rarely innervated by the mandibular branch.
Which of the following structures passes through the pterygomaxillary fissure?
(A) Mandibular artery
(B) Mandibular nerve
(C) Maxillary artery
(D) Maxillary nerve
The correct response is Option C.
The pterygomaxillary fissure appears on lateral cephalograms as an upside-down teardrop. It serves as a radiographic point of orientation. The posterior border of this opening is the anterior aspect of the pterygoid plates. The anterior border is the posterior aspect of the maxilla, and the superior border is the pterygopalatine fossa and sphenoid bone and the orbital process of the palatine bone. The inferior orbital fissure and the pterygomaxillary fissure are oriented at right angles to each other. They are separated by the small pterygopalatine fossa. The pterygomaxillary fissure connects the small pterygopalatine fossa with the much larger infratemporal fossa. It transmits the terminal branches of the maxillary artery and veins. The inferior orbital fissure transmits the maxillary nerve and branches of the pterygopalatine ganglion from the pterygopalatine fossa to the orbit. The mandibular nerve and branches pass through the infratemporal fossa but not through the pterygomaxillary fissure. Appropriate care must be taken during separation of the face from the pterygoid plates to avoid injury to the maxillary artery and veins. After separation of these components, down-fracture is often performed using digital pressure alone.
A neonate has a reddish 1.5-cm mass of the nasal root with overlying cutaneous telangiectasias. A photograph is shown above. On physical examination, the mass is firm, noncompressible, and nonpulsatile. It does not transilluminate or change with Valsalva maneuver. Which of the following is the most likely diagnosis?
(A) Dermoid cyst
(B) Encephalocele
(C) Glioma
(D) Hemangioma
(E) Lipoma
The correct response is Option C.
The findings in this neonate are consistent with a glioma. Nasal gliomas are thought to originate as encephaloceles but fail to maintain their intracranial connections. They may be external, internal, or a combination of both. External gliomas typically appear at or just lateral to the nasal root. They are reddish, firm, noncompressible, lobular lesions that exhibit telangiectasias of the overlying skin, but do not transilluminate or pulsate. Bony defects, intracranial connections, and cerebrospinal fluid leakage occur only rarely. Histologic evaluation shows astrocytic neuroglial cells and fibrous and vascular connective tissue that is covered with skin or nasal mucosa.
A nasal dermoid cyst arises from a dermoid sinus, which is a cutaneous inward passage lined with stratified squamous epithelium. These masses can also be external or internal. An external nasal dermoid is a firm, noncompressible, nonpulsatile lesion that does not transilluminate and may be lobulated. Although bony defects are infrequent, cerebrospinal fluid leakage and meningitis may occur. Nasal dermoid cysts are derived from ectoderm and mesoderm, lined with squamous epithelium, and contain specialized adnexal structures such as hair follicles, pilosebaceous glands, and smooth muscles.
Encephaloceles involve herniation of cranial tissue through a skull defect. They may be classified as meningoceles (containing meninges only), meningoencephaloceles (containing meninges and brain), or meningoencephalocystoceles (containing meninges, brain, and part of the ventricular system). External, or sincipital, encephaloceles are soft, bluish, compressible, pulsatile masses that are located at the nasal root and transilluminate. They typically enlarge with crying and Valsalva maneuver.
Hemangiomas are raised lesions that arise from a proliferation of endothelial cells. Most appear shortly after birth and involute spontaneously after a period of rapid growth. Discoloration of the overlying skin is often associated.
Lipomas are soft, skin colored, compressible lesions that do not have cutaneous telangiectasias and do not transilluminate or pulsate. They may appear at the nasal root, but are not predisposed to that location.
