Head and Neck Congenital Flashcards
Which of the following neural structures does NOT pass through the superior orbital fissure?
(A) Optic (II) nerve
(B) Oculomotor (III) nerve
(C) Trochlear (IV) nerve
(D) Abducens (VI) nerve
(E) Sympathetic nerve fibers
The correct response is Option A.
The superior orbital fissure transmits the oculomotor (III), trochlear (IV), and abducens (VI) nerves and sympathetic nerve fibers from the cavernous plexus. In patients who sustain high-velocity fractures of the orbital roof, the fractures may extend to involve the structures of the superior orbital fissure, resulting in a condition known as superior orbital fissure syndrome. This syndrome manifests as loss of ocular motion resulting from paralysis of the motor nerves that pass through the superior orbital fissure, but does not affect vision.
The optic (II) nerve and ophthalmic artery pass through the optic foramen, which is separated from the superior orbital fissure by the lesser wing of the sphenoid bone. Orbital apex syndrome, which involves injury to the optic nerve resulting from extension of the fracture into the optic canal, is characterized by loss of vision.
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.
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.
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,
Which of the following cranial nerves provides innervation to the temporalis muscle?
(A) Ophthalmic division of the trigeminal nerve (V1)
(B) Maxillary division of the trigeminal nerve (V2)
(C) Mandibular division of the trigeminal nerve (V3)
(D) Abducens (VI) nerve
(E) Facial (VII) nerve
The correct response is Option C.
The temporalis muscle receives its innervation primarily from the branches of the mandibular division of the trigeminal nerve (V3), which then exits the skull via the foramen ovale. The motor branches of the buccal, masseteric, and mandibular nerves are derived from V3 and act to innervate the temporalis muscle. This muscle is a large, powerful muscle of mastication that originates along the temporal crest of the skull and inserts into the coronoid process of the mandible.
The ophthalmic division of the trigeminal nerve (V1) provides sensation to the forehead and anterior scalp; this nerve branch exits the skull through the supraorbital foramen.
The maxillary division of the trigeminal nerve (V2) provides sensation to the cheek and upper lip and to the upper teeth via the superior alveolar nerve. This nerve branch is transmitted through the infraorbital foramen.
The abducens (VI) nerve provides motor innervation into the lateral rectus muscle of the eye.
The facial (VII) nerve provides motor innervation to the muscles of facial expression.
Which of the following structures drains into the inferior meatus?
(A) Anterior ethmoid air cells
(B) Frontal sinus
(C) Maxillary sinus
(D) Nasolacrimal duct
(E) Sphenoid sinus
The correct response is Option D.
Knowledge of the anatomy of the sinuses is important in the management of patients who have fractures of the frontal sinus. Patency of the drainage system, including the frontonasal and nasolacrimal ducts, must be assessed, as occlusion of the ducts may result in the development of infection or mucocele.
The nasolacrimal duct drains into the inferior meatus. In contrast, the anterior ethmoid air cells and maxillary sinus drain into the middle meatus; the frontal sinus also drains into the middle meatus via the frontonasal duct. The sphenoid sinus drains into the sphenoethmoid recess, which is found above and behind the superior concha.
Which of the following structures is a branch of the mandibular division of the trigeminal nerve?
(A) Infraorbital nerve
(B) Lingual nerve
(C) Nasopalatine nerve
(D) Posterosuperior alveolar nerve
(E) Posterosuperior nasal nerve
The correct response is Option B.
The lingual nerve, which supplies sensation to the anterior two thirds of the tongue, is a branch of the mandibular division of the trigeminal nerve (V3). Other structures that arise from this nerve include the inferior alveolar nerve, which supplies sensation to the mandibular teeth; the long buccal branch, which supplies sensation to the buccal mucosa; and the mental nerve, which supplies sensation to the skin of the chin and lower lip and the mucosa of the lip and adjacent gingiva. In addition, the auriculotemporal nerve divides from the posterior border of V3 immediately after exiting the foramen ovale, passes around the middle meningeal artery as two units, and then courses between the external auditory canal and temporomandibular joint (TMJ). This nerve supplies sensory innervation to the anterior auricle, a large portion of the temporal region, and part of the external auditory canal and gives off a branch to supply the TMJ.
The infraorbital nerve, nasopalatine nerve, posterosuperior alveolar nerve, and posterosuperior nasal nerve are branches of the maxillary division of the trigeminal nerve (V2).
A 2-year-old boy presents with swelling over the bridge of the nose that has been present since birth. The swelling has been slowly increasing in size and he has hypertelorism. The swelling is soft, compressible, and it transilluminates. There are visible and palpable pulsations, and the mass enlarges when the patient cries. Which of the following is the most likely diagnosis?
A)Encephalocele
B) Glioma
C) Hemangioma
D) Nasal dermoid cyst
E) Nasopharyngeal angiofibroma
The correct response is Option A.
Encephaloceles are neural tube defects that result in sac-like protrusions of the meninges (meningocele) or brain and meninges (meningoencephalocele) in various locations along the cranium, such as between the forehead and nose (including naso-orbital, frontonasal, and nasoethmoidal locations) or on the back of the skull. They tend to be soft, compressible masses that transilluminate that may be sessile or pedunculated. Biopsy may result in a cerebrospinal fluid leak.
Glioma is a mass of ectopic neural tissue that does not transilluminate.
Hemangiomas are benign vascular lesions that are present at birth and characterized by a rapid growth phase around the age of 1 to 6 months, followed by gradual involution over 1 to 12 years. They have no intracranial connection and no cerebral pulsations. Nasopharyngeal angiofibromas, also known as juvenile nasopharyngeal angiofibromas, are benign but locally invasive vascular tumors that occur almost exclusively in adolescent males. They present with unilateral or bilateral nasal obstruction, frequent epistaxis or blood-tinged nasal discharge. Nasal dermoid cyst is a benign cystic lesion that does not pulsate and does not transilluminate.
In addition to the zygoma, which of the following bones forms the lateral orbital wall?
(A) Frontal bone
(B) Greater wing of the sphenoid
(C) Lacrimal bone
(D) Lesser wing of the sphenoid
(E) Maxilla
The correct response is Option B.
The lateral orbital wall is formed primarily by the orbital surface of the zygomatic bone and the greater wing of the sphenoid bone. In addition to the greater wing of the sphenoid, other bones that comprise the orbit include the ethmoid, frontal bone, lacrimal bone, maxilla, palatine bone, and the lesser wing of the sphenoid. The sphenoid portion of the lateral wall is separated from the roof of the orbit by the superior orbital fissure and from the floor of the orbit by the inferior orbital fissure.
Appropriate anatomic reduction of the greater wing of the sphenoid and lateral wall of the orbit is critical for adequate reduction of a fracture of the zygomaticomaxillary complex. Because correct reduction of the inferior orbital rim, zygomaticofrontal suture, and orbital floor does not ensure reduction of the lateral wall, the surgeon should verify that the complete reduction of all structures has been performed.
Which of the following best describes the pathway of the accessory (XI) nerve after it enters the posterior triangle of the neck?
(A) Within the subcutaneous fat
(B) Within the carotid sheath
(C) Within the inferior portion of the sternocleidomastoid muscle
(D) Deep to the investing fascia
(E) Deep to the prevertebral fascia
The correct response is Option D.
The accessory nerve descends through the jugular foramen into the neck between the internal carotid and internal jugular vein. It crosses the internal jugular vein and is joined by fibers from the ventral ramus of C2. It gives off a motor branch to the sternocleidomastoid muscle before passing deep to or through this muscle. It emerges on the posterior border of the sternocleidomastoid muscle always in the upper half of this muscle. It enters the posterior triangle of the neck passing obliquely across the floor over the levator scapulae just deep to the investing fascia and superficial to the prevertebral fascia. It supplies motor fibers to the trapezius.
A 55-year-old woman has numbness of the earlobe after undergoing biopsy of an internal jugular lymph node. The most likely cause is injury to which of the following structures?
(A) Auricular branch of the vagus nerve
(B) Auriculotemporal nerve
(C) Great auricular nerve
(D) Posterior auricular nerve
(E) Ventral ramus of the first cervical root
The correct response is Option C.
This 55-year-old woman has numbness of the earlobe due to injury to the great auricular nerve. This nerve arises from the second and third cervical nerves and emerges from the posterior border of the sternocleidomastoid muscle, then travels anterosuperiorly between the sternocleidomastoid and platysma muscles and divides into auricular, facial, and mastoid branches. The auricular branch provides sensation to the earlobe and posterior two thirds of the ear and is prone to injury during surgery in the region of the upper lateral neck.
The auricular branch of the vagus nerve, also known as Arnold’s nerve, arises from the superior ganglion, receives a contribution from the glossopharyngeal nerve, and travels along the temporal bone, emerging through the auricular fissure between the mastoid process and external auditory meatus. It supplies sensation to the posterior aspect of the ear and external auditory meatus.
The auriculotemporal nerve is a sensory branch of the trigeminal nerve. This nerve branch courses posterior to the external pterygoid muscle, emerges from beneath the parotid gland, crosses the zygoma, and travels in a superior direction. The anterior auricular branches of this nerve supply sensory innervation to the anterior upper helix and tragus.
The posterior auricular nerve arises from the facial nerve at the stylomastoid foramen, receives a contribution from the auricular branch of the vagus nerve, and supplies two nerve branches, one of which joins with the mastoid branch of the great auricular nerve and another that joins with the lesser occipital nerve. Both branches provide sensibility to the posterior side of the pinna and the concha. The posterior auricular nerve supplies motor innervation to the posterior auricular and occipitalis muscles.
The ventral ramus of the first cervical root courses parallel to the vertebral artery and supplies motor innervation to the rectus capitis muscles.
Which of the following provides the drainage ostium for the nasolacrimal duct into the nose?
(A) Inferior meatus
(B) Middle meatus
(C) Superior meatus
(D) Supreme meatus
The correct response is Option A.
The inferior meatus provides the drainage ostium for the nasolacrimal duct into the nose. The maxillary, frontal, and anterior ethmoidal sinuses drain into the middle meatus, while the posterior ethmoid cells drain into the superior meatus. The sphenoid sinus drains into the supreme meatus, also referred to as the sphenoethmoidal recess.
The palatine bone contributes to which of the following structures?
(A) Anterior nasal spine
(B) Dental arch
(C) External nose
(D) Hamulus
(E) Orbit
The correct response is Option E.
The palatine bone is located posterior to the maxilla and pterygoid lamina; it is composed of horizontal and pyramidal processes. The horizontal process contributes to the posterior aspect of the hard palate and becomes the floor of the choana. The pyramidal process extends vertically to contribute to the floor of the orbit.
The anterior nasal spine is a prominence of the maxillary bone.
The dental arch lies anterior to the palatine bone because it includes a portion of the maxilla. The hamulus extends inferiorly from the medial pterygoid plate, posterior to the palatine bone.
The external nose is comprised of the paired nasal bones and frontal processes of the maxilla.
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.
Which of the following structures is derived from the second branchial arch?
(A) Incus
(B) Malleus
(C) Sphenoid (greater wing)
(D) Stapes
(E) Temporal bone (squamous portion)
The correct response is Option D.
The stapes is derived from Reichert’s cartilage, which is the precursor of the second branchial arch. Other structures derived from the second branchial arch include the stylohyoid process, the lesser cornu of the hyoid bone, and the upper part of the body of the hyoid bone.
The other two ossicles of the middle ear (malleus and incus) are derived from the first branchial arch. Cartilage precursors in the first branchial arch are the quadrate cartilage and Meckel’s cartilage, both of which give rise to skeletal elements through endochondral ossification. The quadrate cartilage gives rise to the greater wing of the sphenoid bone and the incus, while Meckel’s cartilage gives rise to the malleus and the mandibular condyles.
The skeletal elements of the maxillary and mandibular prominences originate from intramembranous ossification, which is derived from direct ossification of the dermal mesenchyme of the arches. The maxillary prominence gives rise to the maxilla, zygoma, and squamous portion of the temporal bone. The mandibular prominence gives rise to the body and ramus of the mandible.
Intracranial communication of a frontonasal encephalocele is most likely to occur through which of the following anatomic structures?
(A) Cribriform plate
(B) Foramen rotundum
(C) Foramen ovale
(D) Foramen cecum
(E) Superior orbital fissure
The correct response is Option D.
Intracranial communication of a frontonasal encephalocele is most likely to occur through the foramen cecum because anterior encephaloceles herniate through this foramen. In contrast, the cribriform plate transmits the fibers of the olfactory nerve, the foramen rotundum transmits the maxillary division of the trigeminal nerve (V2), and the foramen ovale transmits the mandibular division of the trigeminal nerve (V3). The superior orbital fissure transmits the oculomotor (III), trochlear (IV), and abducens (VI) nerves, as well as the ophthalmic division of the trigeminal nerve (V1).
Which of the following muscles can function to close off the oral cavity from the oropharynx?
(A) Levator veli palatini
(B) Musculus uvulae
(C) Palatoglossus
(D) Palatopharyngeus
(E) Tensor veli palatini
The correct response is Option C.
The palatoglossus is a paired muscle that elevates the posterior tongue and pulls it against the soft palate, separating the oral cavity from the oropharynx. The muscle attaches to the side of the tongue on one end and the palatine aponeurosis on the other.
The levator veli palatini elevates the soft palate during swallowing and yawning. It attaches superiorly to the cartilage of the auditory tube and the petrous part of the temporal bone and inferiorly to the palatine aponeurosis.
The palatopharyngeus muscle is part of the palatopharyngeal arch, attaching to the lateral wall of the pharynx, the hard palate, and the palatine aponeurosis. During swallowing, it tenses the soft palate while pulling the walls of the pharynx superiorly, medially, and anteriorly, effectively closing off the nasopharynx from the oropharynx.
The tensor veli palatini also tenses the soft palate and opens the eustachian tube during yawning and swallowing. It extends from the palatine aponeurosis to the medial pterygoid plate and spine of the sphenoid bone and the cartilage of the eustachian tube.
The musculus uvulae pulls the uvula superiorly and shortens it. The muscle fills the substance of the uvula, attaching to its mucosa and to the posterior nasal spine and palatine aponeurosis.
Which of the following muscles of the palate is innervated predominantly by the trigeminal (V) nerve?
(A) Levator veli palatini
(B) Musculus uvula
(C) Palatoglossus
(D) Palatopharyngeus
(E) Tensor veli palatini
The correct response is Option E.
The tensor veli palatini muscle is innervated predominantly by the mandibular branch of the trigeminal nerve (V3). In contrast, the other palatal muscles, including the levator veli palatini, musculus uvula, palatoglossus, and palatopharyngeus, are innervated predominantly by branches of the pharyngeal plexus of the vagus (X) nerve.
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.
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.
Which of the following permanent teeth erupts first?
(A) Central incisor
(B) Lateral incisor
(C) Canine
(D) First premolar
(E) First molar
The correct response is Option E.
The first molar is the first permanent tooth to erupt; this typically occurs between ages 6 and 7 years. The age of mixed dentition, in which there are both deciduous (primary) and permanent (secondary) teeth erupted in the oral cavity simultaneously, begins with the eruption of the first molars. In addition, Angle’s classification, which describes the relationship between the mesiobuccal cusp of the maxillary first molar and the buccal groove of the mandibular first molar, has its basis in this pattern of eruption.
Knowledge of the eruption pattern of the teeth is crucial for management of facial fractures in children, especially for coordination of any necessary bone grafting and/or orthognathic surgery.
The central incisors erupt between ages 6 and 8 years, the lateral incisors between ages 7 and 9 years, the canine teeth between ages 9 and 12 years, and the first premolars between ages 10 and 12 years.
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.
The internal carotid artery supplies which of the following arteries of the scalp?
(A) Frontalis
(B) Occipitalis
(C) Parietal
(D) Posterior auricular
(E) Supraorbital
The correct response is Option E.
The supraorbital and supratrochlear arteries are branches of the internal carotid artery via the ophthalmic artery and, therefore, receive their blood supply from the internal carotid. The arteries of the scalp travel through the subcutaneous fat from the periphery toward the vertex, then anastomose in the midline with branches of the ophthalmic artery. If the internal carotid artery is thrombosed, branches of the external carotid arteries supply blood to the anterior part of the scalp through the angular and ophthalmic arteries.
The frontalis and parietal arteries are branches of the superficial temporal artery, which in turn branches from the external carotid arteries. The occipitalis and posterior auricular arteries are also branches of the external carotid arteries.
During dissection to the level of the digastric tendon in a patient undergoing microsurgical head and neck reconstruction, the hypoglossal nerve can be found in which of the following positions?
(A) Lateral to both the internal and external carotid arteries
(B) Medial to both the internal and external carotid arteries
(C) Lateral to the internal carotid artery and medial to the external carotid artery
(D) Medial to the internal carotid artery and lateral to the external carotid artery
The correct response is Option A.
During preparation of recipient vessels for free tissue transfer in a patient undergoing head and neck reconstruction, the branches of the carotid artery and internal jugular vein are dissected. The digastric tendon is divided or retracted, and then the carotid artery and hypoglossal nerve are exposed. The hypoglossal nerve passes between the internal carotid artery and internal jugular vein. It turns anteriorly, spiraling around the internal carotid artery, and passes under the occipital artery. It then loops across the lateral surface of the external carotid artery and passes deep to the insertion of the stylohyoid muscle and digastric sling before disappearing beneath the posterior edge of the mylohyoid muscle. The surgeon must take great care to avoid injuring the hypoglossal nerve because injury would lead to impaired tongue mobility and potential difficulties with speech and swallowing.
Each of the following is a muscle of mastication EXCEPT the
(A) buccinator
(B) lateral pterygoid
(C) masseter
(D) medial pterygoid
(E) temporalis
The correct response is Option A.
The lateral and medial pterygoids, masseter, and temporalis muscles are muscles of mastication, capable of exerting force on the mandible. These muscles are innervated by the mandibular division of the trigeminal nerve (V3).
The lateral pterygoid muscle has two heads, which arise from the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone and the lateral surface of the lateral pterygoid plate, and insert on the mandibular neck and the articular capsule and disk of the temporomandibular joint. This muscle pulls the condylar process of the mandible and articular disk forward, opening the mouth.
The medial pterygoid muscle arises from the medial surface of the lateral pterygoid plate and the pyramidal process of the palatine bone and inserts on the medial surface of the mandibular ramus and angle. It acts to elevate and protrude the mandible and produce side-to-side movements.
The masseter muscle arises from the zygomatic arch and inserts on the mandibular ramus and coronoid process; during mastication it elevates the mandible to occlude the teeth.
The temporalis muscle arises from the temporal fossa, passes deep to the zygomatic arch, and inserts on the coronoid process and anterior border of the mandibular ramus. This muscle elevates the mandible and contributes to side-to-side grinding movements. The posterior fibers of the temporalis aid in retraction of the mandible once it has been protruded.
The buccinator muscle arises from the alveolar process of the maxilla, from the mandible opposite the molars, and from the anterior border of the pterygoid mandibular raphe; it inserts into the submucosa of the cheeks and lips and is used to compress the cheeks against the teeth and gums. It is innervated by the facial (VII) nerve. Although it is not a muscle of mastication, it assists the tongue in directing food between the molars during mastication.
A 64-year-old man comes to the office because he has numbness of the left medial cheek and infraorbital area. Physical examination shows a mass of the hard palate. Incisional biopsy shows adenoid cystic carcinoma. Further evaluation is most likely to show tumor involvement of which of the following foramina at the base of the skull?
(A) Anterior ethmoid foramen
(B) Foramen ovale
(C) Foramen rotundum
(D) Jugular foramen
(E) Stylomastoid foramen
The correct response is Option C.
Numbness in the left medial cheek and left infraorbital area suggest that the tumor has invaded the infraorbital nerve, which exits the middle cranial fossa from the foramen rotundum. Approximately 80% of patients with adenoid cystic carcinoma have perineural spread. The anterior ethmoid foramen emerges from the frontoethmoid suture line and contains the anterior ethmoid vessels. The foramen ovale and the stylomastoid foramen, respectively, contain the mandibular nerve (V3) and the facial nerve (cranial nerve VII). Cranial nerves IX (glossopharyngeal), X (vagus), and XI (spinal accessory) emerge from the jugular foramen.
A 56-year-old woman undergoes reconstruction of the mandible using a free fibular flap. During the procedure, the microsurgeon dissects the external carotid artery; however, the superior thyroid artery cannot be located for anastomosis. Which of the following branches of the external carotid artery is the next distal vessel that would be suitable for anastomosis?
(A) Lingual
(B) Occipital
(C) Posterior auricular
(D) Maxillary
The correct response is Option A.
During the dissection of the neck vessels, the microsurgeon must be comfortable with the anatomy of the entire neck including the orientation and suitability of the available arteries. The branches of the external carotid artery, in order from proximal to distal, are as follows: superior thyroid, ascending pharyngeal, lingual, occipital, facial, posterior auricular, and maxillary arteries.
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.
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.
Which of the following structures passes though the foramen ovale?
(A) Accessory nerves
(B) Optic (II) nerve
(C) Ophthalmic division of the trigeminal nerve (V1)
(D) Maxillary division of the trigeminal nerve (V2)
(E) Mandibular division of the trigeminal nerve (V3)
The correct response is Option E.
The mandibular division of the trigeminal nerve (V3) passes through the foramen ovale. This foramen is located in the region of the superior orbital fissure, which contains the nerves to the extraocular muscles, sympathetic fibers, and vessels and is found within the middle cranial fossa.
The accessory nerves, glossopharyngeal (IX) nerve, and vagus (X) nerve pass through the foramen jugulare.
The optic foramen transmits the optic (II) nerve and ophthalmic artery.
The ophthalmic division of the trigeminal nerve (V1) passes through the superior orbital fissure.
The foramen rotundum transmits the maxillary division of the trigeminal nerve (V2).
Which of the following best describes the blood supply to the sternocleidomastoid muscle?
(A) One source
(B) One dominant source and one minor source
(C) Two equally dominant sources
(D) Three equally dominant sources
(E) Four equally dominant sources
The correct response is Option D.
The sternocleidomastoid muscle attaches to the mastoid process superiorly and to the clavicle and sternum inferiorly. The blood supply to this muscle is segmental and is derived from three equally dominant sources, each perfusing a portion of the muscle with some internal connections; each portion has its own musculocutaneous perforators that supply a small area of overlying skin. Vascularity to the superior third of the muscle is supplied by a branch of the occipital artery, to the middle third by a branch of the superior thyroid artery, and to the inferior third by a branch of the thyrocervical trunk.
Knowledge of this pattern of arterial anatomy is important when harvesting the muscle for reconstruction of the neck and mandible. If the entire muscle is harvested for use but is based only on the inferior or superior pedicle, the portion of muscle farthest from the pedicle may not be reliable.
Stensen’s duct can be found at which of the following anatomic sites?
(A) At the mandibular angle
(B) At the preauricular border
(C) At the zygomatic arch
(D) Between the superficial and deep lobes of the parotid gland
(E) Within the buccal space
The correct response is Option E.
Stensen’s duct can be found within the buccal space, which is bordered anteriorly by the orbicularis oris muscle, posteriorly by the edge of the masseter muscle, superiorly by the zygomaticus major muscle, and inferiorly by the fascial attachment of the buccinator muscle to the mandible. The duct develops deep within the parotid gland and emerges from the superior third of the gland at its anterior border, then courses below the zygomatic arch and enters the buccal space, inserting into the buccinator and then entering the oral cavity opposite the upper second molar. The facial artery and vein, buccal branches of the facial nerve, and buccal fat pad can also be found within the buccal space.
Although Stensen’s duct and branches of the facial nerve are vulnerable to inadvertent dissection in the area of the parotid gland, there are no major arterial branches in this region.
The external carotid artery can be found within the angle of the mandible, while the superficial temporal artery is located within the preauricular border. The transverse facial artery is found at the zygomatic arch. These locations do not lie within the typical course of Stensen’s duct.
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 23-year-old man comes to the office for evaluation of unilateral blepharoptosis. On examination, the excursion of the eyelid margin is measured from downgaze to upgaze while the eyebrow is manually fixed against the supraorbital rim. Which of the following would best approximate the normal excursion distance of levator function for this patient?
A) 2 to 6 mm
B) 7 to 11 mm
C) 12 to 16 mm
D) 17 to 21 mm
E) 21 to 25 mm
The correct answer is option C
Levator function is measured indirectly by determining the excursion of the eyelid margin as the patient looks from downgaze to upgaze. The eyebrow is manually fixed against the supraorbital rim during this measurement, preventing the frontalis muscle from contributing to eyelid movement. Many patients subconsciously raise their eyebrow in a compensatory effort to elevate the drooping eyelid, a beneficial finding in individuals requiring frontalis suspension. Normal adults typically demonstrate 12 to 16 mm of levator function. Lesser measurements may indicate the presence of a developmental or acquired myopathy.
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.
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.
The papilla of the parotid duct is most commonly located adjacent to which of the following maxillary teeth?
(A) First bicuspid
(B) Second bicuspid
(C) First molar
(D) Second molar
(E) Third molar
The correct response is Option D.
The papilla of the parotid is located most frequently adjacent to the maxillary second molar as it empties the secretions of the parotid gland via Stensen’s duct.
Actions of the levator veli palatini muscle include retracting the soft palate and which of the following?
(A) Closing the eustachian tube
(B) Drawing the uvula anteriorly
(C) Narrowing the faucial isthmus
(D) Opening the eustachian tube
(E) Widening the faucial isthmus
The correct response is Option D.
The soft palate consists of the levator veli palatini muscle as well as the muscles of the uvula and the palatopharyngeus, palatoglossus, and tensor veli palatini muscles. The levator veli palatini muscle raises and retracts the soft palate to bring it in touch with the posterior pharyngeal wall. It also opens the eustachian tube. The uvular muscles draw the uvula superiorly and anteriorly. The palatopharyngeus and palatoglossus muscles lower the soft palate and narrow the faucial isthmus. The tensor veli palatini muscle tenses and lowers the soft palate and opens the eustachian tube.
In the repair of a cleft of the soft palate, the tensor veli palatini muscle is difficult to approximate because the tendon runs over the hamulus. In contrast, the levator veli palatini muscle can be easily approximated. To avoid separation of the tensor tendon, it can be dissected off the hamulus by fracturing the hamulus. Paralysis of the soft palate may cause nasal regurgitation and interfere with speech. In unilateral paralysis of the soft palate, the uvula deviates toward the normal side during elevation.
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 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.
Which of the following structures travels through the foramen rotundum?
(A) First division of the trigeminal (V) nerve
(B) Second division of the trigeminal (V) nerve
(C) Third division of the trigeminal (V) nerve
(D) Optic (II) nerve
(E) Middle meningeal artery
The correct response is Option B.
The maxillary division of the trigeminal nerve travels through the foramen rotundum. The ophthalmic division of the trigeminal nerve travels through the superior orbital fissure. The mandibular division of the trigeminal nerve travels through the foramen ovale. The foramen spinosum carries the middle meningeal artery. The optic nerve travels through the optic foramen.
A 10-month-old boy is brought to the office because of the ocular defect shown in the photograph. Which of the following is the correct term for this anomaly?
A) Anophthalmia
B) Coloboma
C) Congenital cataract
D) Palpebral fissure
E) Tessier No. 6 cleft
Coloboma is a congenital ocular defect of the eyelid, iris, retina, choroid, or optic disk. The defects can range in size from a small notch to a large structural cleft. Palpebral colobomas are thought to arise from a localized growth disturbance, while colobomas of the iris, retina, and optic disk arise from defective closure of the optic fissure. Upper eyelid coloboma rarely affects vision; large defects of the lower eyelid can lead to corneal ulceration. Anophthalmia is total absence of the eye. A congenital cataract is a lens opacity that is present in 1:4000 to 1:10,000 newborns. The size and location determine the effect on vision. The palpebral fissure is the natural opening between the upper and lower eyelids. A Tessier No. 6 cleft involves the inferolateral aspect of the lower eyelid, inferior orbital rim, and the zygoma. This cleft often has an associated lower eyelid coloboma and is related to Treacher Collins syndrome.
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.
The congenital anomaly shown in the photograph is thought to be caused by which of the following?
A) Failure of fusion of the lateral and maxillary nasal processes
B) Failure of fusion of the maxillary prominence with the medial nasal prominence
C)
Failure of fusion of the medial nasal prominence and the lateral nasal prominence
D) Failure of fusion of the medial nasal prominences
E) Failure of the oronasal membrane to rupture
The correct answer is A.
Proboscis lateralis, which is illustrated in the photograph, is thought to be a failure of fusion between the lateral and maxillary nasal processes. A cleft lip is the result of a failure of fusion of the maxillary prominence with the medial nasal prominence. A midline cleft or Tessier Zero cleft is a result of the failure of fusion of the medial nasal prominences. Choanal atresia is a result of a failure of the oronasal membrane to rupture. Finally, a mandibular cleft or Tessier # 30 cleft is a result of the failure of fusion of the mandibular prominences.
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.
A patient sustains a laceration of the superior helix of the auricle. Adequate anesthesia is most likely to be obtained with block of which of the following nerves?
(A) Facial (VII)
(B) Glossopharyngeal (IX)
(C) Great auricular
(D) Trigeminal (V)
(E) Vagus (X)
The correct answer is option D
 Superior auricle is innervated by the auriculotemporal nerve, a branch of the mandibular branch of trigeminal (CN V3)
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 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.
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.
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.
Which of the following anatomic structures of the ear originates from the second (hyoid) pharyngeal arch?
(A) Antitragus
(B) Helical root
(C) Superior helix
(D) Tragus
The correct response is Option A.
During the sixth week of fetal gestation, the anatomic subunits of the auricle arise from six hillocks that are derived from the first and second pharyngeal arches.
The anterior three hillocks from the first (or mandibular) pharyngeal arch ultimately develop into the tragus, helical root, and superior helix.
The antihelix, antitragus, inferior helix, and lobule form from the fourth through sixth posterior hillocks from the second (or hyoid) pharyngeal arch.
The structures that arise from the first pharyngeal arch typically drain into the parotid lymph nodes, and structures from the second pharyngeal arch drain into the cervical lymph nodes.
A 9-year-old boy is brought to the office for evaluation of a nodule on the neck that appeared 1 week ago. The nodule measures 2cm and is slightly to the right of midline. A photograph is shown. The lesion is slightly tender. Which of the following is the most appropriate management of this lesion?
A) Excision of lesion with any tract and a section of hyoid bone
B) Excision of lesion with any tract and a section of thyroid cartilage
C) Excision of lesion with any tract only
D) Fine needle aspiration with cytology
E) Intralesional sclerotherapy under image guidance
The correct answer is option A.
Thyroglossal duct cysts are neck lesions that usually present during childhood, often after a localized inflammation or infection. They are usually neck lesions near the midline. Some may move with swallowing if they are close to the base of the tongue, but not all exhibit this finding. The congenital thyroglossal duct is the remnant of the descent of the developing thyroid gland, and it runs from the foramen cecum of the base of the tongue, down to the thyroid. Imaging is typically by ultrasound, but other modalities, including radioisotope scans to rule out ectopic thyroid tissue or confirm the location of the normal thyroid gland, have been suggested to avoid excising ectopic thyroid gland.
The Sistrunk procedure shows less recurrence and is a complete excision, including any associated tract, and about a 1-cm section of hyoid bone. Although proposed in 1928, this is still the most commonly recommended approach for thyroglossal duct cysts.
Fine-needle aspiration is appropriate for thyroid nodules, which are unlikely to present in an acute manner in this population.
Sclerotherapy is used for vascular anomalies and likely would have presented earlier on in childhood.
