In-Service Exam
Head + Neck Anatomy - 2001





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.

Reference
1. Clemente CD, ed. Gray's Anatomy of the Human Body. 13th ed. Philadelphia, Pa: Lea & Febiger; 1985:28-31.

An 8-year-old boy has had a painless mass in the midline of the neck that has slowly enlarged over the past two years. This finding is most consistent with

(A) branchial cleft cyst
(B) dermoid cyst
(C) laryngocele
(D) lymphatic malformation
(E) thyroglossal duct cyst

The correct response is Option E.

This 8-year-old boy has a thyroglossal duct cyst, a slowly enlarging, painless mass of the midline of the neck that results from incomplete degeneration of the thyroglossal duct before birth. This duct connects an endodermal diverticulum (which later becomes the thyroid gland) to the foramen cecum in the developing fetus; in most cases, the duct degenerates once the diverticulum becomes a solid gland. Although thyroglossal duct cysts can be found from the base of the tongue to the cricoid cartilage, most cysts are located inferior to the hyoid bone. Infection and rupture are fairly uncommon; if these occur, antibiotics should be administered. Definitive management of a thyroglossal duct cyst is complete surgical excision of the cyst and central portion of the hyoid bone; this is known as the Sistrunk procedure.

Branchial cleft cysts rarely occur in the midline of the neck. Instead, most of these cysts develop from remnants of the second branchial cleft and are found at the anterior border of the sternocleidomastoid muscle. Dermoid cysts are also rare in the neck and are more likely to affect the nasion, lateral brow, or calvarium. A laryngocele is an air pocket that normally communicates with the larynx and often enlarges with coughing or other changes in pressure within the trachea; the report of a slowly enlarging, painless mass would not be expected to describe a laryngocele. Lymphatic malformations are present at birth and would not be seen in the midline of the neck. Because these malformations do not occur in a specific plane, diffuse involvement of head and neck tissues is common.

References
1. Gosain AK, Moore FO. Embryology of the head and neck. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:223-236.
2. Lee KJ. Thyroid and parathyroid glands. In: Essential Otolaryngology Head & Neck Surgery. 7th ed. Stanford, Ct: Appleton & Lange; 1995:574-575.

Patients with paralysis of the trigeminal nerve have loss of function of which of the following muscles?

(A) Levator veli palatini
(B) Palatopharyngeus
(C) Stylohyoid
(D) Stylopharyngeus
(E) Tensor veli palatini

The correct response is Option E.

Because the tensor veli palatini muscle receives its motor innervation from the trigeminal (V) nerve, a patient who has paralysis of this nerve will experience a loss of function of the tensor veli palatini, which is a derivative of the first branchial arch. In contrast, the anatomically adjacent levator veli palatini muscle is a derivative of the fourth branchial arch and is innervated by the superior laryngeal branch of the vagus (X) nerve. The palatopharyngeus muscle has this same origin and innervation. The stylohyoid muscle is derived from the second branchial arch and innervated by the facial (VII) nerve, while the stylopharyngeus muscle is derived from the third branchial arch and innervated by the glossopharyngeal (IX) nerve.

References
1. Gosain AK, Moore FO. Embryology of the head and neck. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith's Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:223-236.
2. Greene RM, Weston WM. Craniofacial embryology. In: Cohen M, ed. Mastery of Plastic and Reconstructive Surgery. Boston, Mass: Little, Brown & Co; 1994;1:459-470.
3. Moore KL, ed. The Developing Human. 4th ed. Philadelphia, Pa: WB Saunders Co; 1988:170-206.

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.

References
1. Agur AM, Lee MJ. The neck. In: Gardner JN, ed. Grant's Atlas of Anatomy. 9th ed. Baltimore, Md: Williams & Wilkins; 1995;7:556-557.
2. Pick TP, Howden R, eds. Gray's Anatomy. New York, NY: Bounty Books; 1977:735-762.

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).

References
1. Hollinshead WH, ed. Anatomy for Surgeons. Philadelphia, Pa: JB Lippincott Co; 1982;1:93-155.
2. Rosse C, Gaddum-Rosse P, eds. Hollinshead's Textbook of Anatomy. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:767-793.

A 42-year-old man is scheduled to undergo surgical excision of a lesion of the lower lip. During anesthetic blockade of the mental nerve prior to the procedure, the nerve foramen can be located beneath the apex of which of the following mandibular teeth?

(A) Central incisor
(B) Cuspid
(C) First molar
(D) Lateral incisor
(E) Second bicuspid

The correct response is Option E.

During anesthetic blockade of the mental nerve, the nerve foramen can be found beneath the apex of the second bicuspid tooth. This nerve, which is the terminal branch of the inferior alveolar nerve, supplies sensory innervation to the skin and mucous membranes of the lower lip as well as the skin of the anterior mandible and chin.

It is important to have knowledge of the location of the mental nerve and its foramen in order to prevent injury during reduction of anterior mandibular fractures or osseous sliding genioplasty procedures.

Because the inferior alveolar nerve is a branch of the mandibular division of the trigeminal nerve (V3), it may be injured during sagittal split osteotomy procedures. Affected patients will have numbness in the distribution of the inferior alveolar nerve postoperatively.

References
1. Ferraro JW, Polayes IM. Local anesthesia and infiltration techniques. In: Ferraro JW, ed. Fundamentals of Maxillofacial Surgery. New York, NY: Springer-Verlag; 1997:158-168.
2. Zide BM, Swift R. How to block and tackle the face. Plast Reconstr Surg. 1998;101:840-851.

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.

References
1. Alvi A, Myers EN, Carrau RL. Malignant tumors of the salivary glands. In: Myers EN, Suen JY, eds. Cancer of the Head and Neck. Philadelphia, Pa: WB Saunders Co; 1996:525-527.
2. Pick TP, Howden R, eds. Gray's Anatomy. New York, NY: Bounty Books; 1977:884-886.

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.

References
1. Hollinshead HW, Rosse C. Head and neck anatomy. In: Textbook of Anatomy. 4th ed. Philadelphia, Pa: Harper & Row, Inc; 1985:895-899.
2. Salmons S. Muscles and fasciae of the head. In: Gray's Anatomy. 38th ed. New York, NY: Churchill Livingstone, Inc; 1995:796-802.

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.
References
1. Gray H. The respiratory system. In: Goss CM, ed. Anatomy of the Human Body. Philadelphia, Pa: Lea & Febiger; 1973:1111-1140.
2. Ricciardelli E, Persing JA. Anatomy/physiology/embryology. In: Ruberg RL, Smith DJ, eds. Plastic Surgery: A Core Curriculum. Saint Louis, Mo: CV Mosby Co; 1994:251-270.