Anatomy Parotid Gland Face
Questions and Answers
- 1.
Loss of sensation from the temporal region and loss of secretory function of the parotid gland would be caused by interruption of which nerve?
- A.
Auriculotemporal
- B.
Chorda tympani
- C.
Deep temporal, posterior
- D.
Facial
- E.
Great auricular
Correct Answer
A. AuriculotemporalExplanation
The auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve (V3). It has two important functions: First, it carries postganglionic parasympathetic fibers to the parotid gland. These fibers come from the otic ganglia, where they synapsed with the presynaptic fibers from the glossopharyngeal nerve (CN IX). Second, the auriculotemporal nerve provides sensory innervation to the skin of anterosuperior ear, part of the external auditory meatus, and the temporomandibular joint. So, the listed symptoms match with an injury to the auriculotemporal nerve.
Chorda tympani is a branch of the facial nerve that provides secretomotor innervation to the submandibular and sublingual glands. It carries preganglionic parasympathetic axons to the submandibular ganglion. In the infratemporal fossa, chorda tympani joins the lingual nerve--it continues with the lingual nerve to the tongue where it supplies taste to the anterior 2/3 of the tongue. The posterior deep temporal nerve is a branch of the mandibular division of the trigeminal nerve which supplies motor innervation to temporalis. The facial nerve (CN VII) innervates all of the muscles of facial expression, and, through the chorda tympani, provides secremotor innervation to the submandibular and sublingual glands as well as taste sensation to the anterior 2/3 of the tongue. Finally, the great auricular nerve comes from the cervical plexus--it provides sensory innervation to the skin of the ear and the skin below the ear.Rate this question:
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- 2.
An elderly man presented with severe pain beneath the left eye, radiating into the lower eyelid, lateral side of the nose and upper lip. What nerve was involved?
- A.
Buccal
- B.
Infraorbital
- C.
Mental
- D.
Supratrochlear
- E.
Zygomatic
Correct Answer
B. InfraorbitalExplanation
The infraorbital nerve is a cutaneous nerve from the maxillary division of trigeminal nerve (V2). It innervates the skin of the lateral nose, lower eyelid, upper lip and zygomatic region. This is exactly where this man's pain is, so it seems like his pain must be transmitted on the infraorbital nerve. The buccal branch of the trigeminal nerve is part of the mandibular division (V3)--this nerve provides sensory innervation to the skin of the cheek and the mucosal lining the cheek. It is not a motor nerve--only sensory! (NOTE: The buccal nerve is NOT the same as the buccal branch of the facial nerve. The buccal branch of the facial nerve is a motor nerve only--it innervates several muscles of facial expression. It does not have a sensory component--only motor!) The mental nerve is a branch of the inferior alveolar nerve, which is a branch of the mandibular division of the trigeminal nerve (V3). It provides sensory innervation to the skin of the chin and lower lip. The supratrochlear nerve is a branch of the frontal nerve, from the ophthalmic division of the trigeminal nerve. It gives sensory innervation to the skin of the medial forehead and the medial part of the upper eyelid. The zygomatic nerve is part of the maxillary division of the trigeminal nerve (V2). It provides sensory innervation to the skin of the face lateral and superior to the orbit. For a good picture of these nerves, see Netter Plate 18.Rate this question:
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- 3.
During a face lift operation on a 48-year-old woman, the plastic surgeon inadvertently cut the marginal mandibular branch of the facial nerve. Which of the following muscles would be paralyzed because of the injury?
- A.
Buccinator
- B.
Depressor anguli oris
- C.
Levator anguli oris
- D.
Levator labii superioris
- E.
Stylohyoid
Correct Answer
B. Depressor anguli orisExplanation
The marginal mandibular branch of the facial nerve provides motor innervation to the muscles of facial expression near the lower lip and chin--right where you find depressor anguli oris. So, if the marginal mandibular branch of the facial nerve was injured, depressor anguli oris would be paralyzed. The buccal branches of the facial nerve provide motor innervation to the buccinator muscle and the muscles of the upper lip (levator anguli oris and levator labii superioris). Finally, stylohyoid is innervated by the facial nerve shortly after exiting the stylomastoid foramen--it is not innervated by any of the special branches of the facial nerve that innervate the muscles of facial expression.Rate this question:
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- 4.
As a result of a face lift operation, a 46-year-old woman noticed an asymmetry of the inferior lip and could not fully depress the angle of her mouth on the right side. Which of the following nerves was most likely damaged during the surgery?
- A.
Zygomatic (VII)
- B.
Buccal (VII)
- C.
Mental (V3)
- D.
Marginal mandibular (VII)
- E.
Infraorbital (V2)
Correct Answer
D. Marginal mandibular (VII)Explanation
Depressor anguli oris is the muscle that depresses the angle of the lip--it is innervated by the marginal mandibular branch of the facial nerve. So, if the marginal mandibular branch of the facial nerve was injured, depressor anguli oris would be paralyzed. The zygomatic branches of the facial nerve innervate the muscles of facial expression that are right around the eye, including orbicularis oculi. The buccal branches of the facial nerve innervate the buccinator muscle and other muscles of facial expression that are near the upper lip, like levator anguli oris and levator labii superioris. The mental and infraorbital branches of the trigeminal nerve provide sensory innervation to the skin of the face--they do not innervate any muscles! The mental nerve, a branch of V3 (mandibular division), innervates the skin of the chin and the lower lip. The infraorbital nerve, a branch of V2 (maxillary division), innervates the skin of the lateral nose, lower eyelid, upper lip, and zygomatic region.Rate this question:
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- 5.
An elderly woman complained of a severe pain, felt above the right eye radiating to the upper eyelid, side of the nose and forehead. Branches of which of the following nerves convey pain sensations from areas of the skin described?
- A.
Maxillary (V2)
- B.
Greater auricular nerve
- C.
Ophthalmic (V1)
- D.
Mandibular (V3)
- E.
Facial (VII)
Correct Answer
C. Ophthalmic (V1)Explanation
The ophthalmic division of the trigeminal nerve provides sensory innervation to the skin of the nose, upper eyelid, and forehead. This is exactly where this woman feels pain, so the ophthalmic division of the trigeminal nerve must be the nerve transmitting the pain. The maxillary division of the trigeminal nerve (V2) provides sensory innervation to the skin of the side of the nose, the cheek, lower eyelid, and upper lip. The mandibular division of the trigeminal nerve (V3) provides sensory innervation to the skin of the chin, lower lip, and lower jaw. The great auricular nerve is a branch of the cervical plexus which supplies sensory innervation to the ear region. Finally, the facial nerve is mostly a motor nerve--it only supplies taste to the anterior 2/3 of the tongue and gives some sensory innervation to the skin of the exernal auditory meatus.Rate this question:
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- 6.
Due to multiple salivary calculi (stones) in the submandibular duct, the submandibular gland of a 45-year-old individual was surgically removed. What major artery directly related to the gland was of special concern to the surgeon?
- A.
Lingual
- B.
Superior thyroid
- C.
Facial
- D.
Ascending pharyngeal
- E.
Maxillary
Correct Answer
C. FacialExplanation
The facial artery arises from the external carotid and winds toward the inferior border of the mandible, crossing over the submandibular gland. So, if the submandibular gland was removed, the facial artery might be damaged. The lingual artery is a branch of the external carotid that runs in the floor of the mouth. It is associated with the submandibular duct, but not with the gland itself. The superior thyroid artery is a branch of the external carotid which travels anteroinferiorly to supply the upper pole of the thyroid. The ascending pharyngeal artery is a posterior branch of the external carotid which supplies blood to the pharynx. Finally, the maxillary artery is one of the two terminal branches of the external carotid artery--it supplies blood to the maxillary region, muscles of mastication, infratemporal fossa, and deep face. Take a look at Netter Plate 63 to get a better picture of this!Rate this question:
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- 7.
To study the compensatory response of selective suprahyoid muscles in elevating the hyoid bone, an experiment was designed in which the posterior belly of the digastric and stylohyoid muscles were paralyzed by drugs. The muscular branches of which of the following nerves must be chemically interrupted to produce paralysis in both muscles?
- A.
Inferior alveolar
- B.
Facial
- C.
Hypoglossal
- D.
Glossopharyngeal
- E.
Lingual
Correct Answer
B. FacialExplanation
The facial nerve (CN VII) provides motor innervation to the posterior belly of the digastric and the stylohyoid muscle. The inferior alveolar nerve is a branch of the mandibular division of the trigeminal nerve (V3) that innervates mylohyoid and the anterior belly of the digastric. The hypoglossal nerve (CN XII) supplies motor innervation to the intrinsic and extrinsic muscles of the tongue, with the exception of palatoglossus. The glossopharyngeal nerve (CN IX) provides motor innervation to stylopharyngeus. Finally, the lingual nerve is a sensory branch of the mandibular division of the trigeminal nerve (V3) which supplies general sense from the anterior 2/3 of the tongue and floor of the mouth.Rate this question:
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- 8.
Which nerve provides motor innervation to the buccinator muscle?
- A.
Auriculotemporal nerve
- B.
Buccal branches of VII
- C.
Buccal nerve
- D.
Mandibular division of V
- E.
Marginal mandibular nerve
Correct Answer
B. Buccal branches of VIIExplanation
The buccal branches of the facial nerve provide motor innervation to the buccinator muscle. Remember, these buccal branches of the facial nerve are motor nerves only--they do not do any sensory innervation. Don't mix this nerve up with the buccal nerve, which is a branch of the mandibular division of the trigeminal nerve (V3)! The buccal nerve is a sensory nerve only--it does not innervate any muscles; it only gives sensory innervation to the skin of the cheek and the mucosal lining of the cheek. The auriculotemporal nerve is also part of the mandibular division of the trigeminal nerve--it carries the postganglionic parasympathetic fibers to the parotid gland and provides sensory innervation to the skin of the anterosuperior ear, part of the external auditory meatus, and the temporomandibular joint. The marginal mandibular nerve is another branch of the facial nerve--it innervates the muscles of facial expression on the lower lip and chin.Rate this question:
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- 9.
Which nerve provides cutaneous innervation to the skin of the angle of the mandible?
- A.
Auriculotemporal nerve
- B.
Lesser petrosal nerve
- C.
Buccal branches of VII
- D.
Marginal mandibular nerve
- E.
Great auricular nerve
Correct Answer
E. Great auricular nerveExplanation
The great auricular nerve is a branch of the cervical plexus that provides cutaneous innervation to the skin of the ear and skin below the ear, including the angle of the mandible. The auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve (V3) with two important functions. First, it carries postganglionic parasympathetic fibers to the parotid gland. Second, the auriculotemporal nerve provides sensory innervation to the skin of anterosuperior ear, part of the external auditory meatus, and the temporomandibular joint. The lesser petrosal nerve is not a sensory nerve--it is a branch of the glossopharyngeal nerve that carries preganglionic fibers to the otic ganglia. Finally, the buccal branches and marginal mandibular branches of the facial nerve are motor nerves only--not sensory nerves! The buccal branches of the facial nerve innervate the buccinator and the other muscles of facial expression above the lip. The marginal mandibular branch innervates the muscles of facial expression of the lower lip and chin.Rate this question:
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- 10.
Which nerve carries postganglionic parasympathetic fibers to the parotid gland?
- A.
Auriculotemporal nerve
- B.
Lesser petrosal nerve
- C.
Glossopharyngeal nerve
- D.
Great auricular nerve
- E.
Marginal mandibular nerve
Correct Answer
A. Auriculotemporal nerveExplanation
The auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve (V3). It has two important functions: First, it carries postganglionic parasympathetic fibers to the parotid gland. These fibers come from the otic ganglia, where they synapsed with the presynaptic fibers from the glossopharyngeal nerve (CN IX). These presynaptic fibers were carried to the otic ganglia by the lesser petrosal nerve. Second, the auriculotemporal nerve provides sensory innervation to the skin of anterosuperior ear, part of the external auditory meatus, and the temporomandibular joint.
The great auricular nerve is a sensory nerve from the cervical plexus--it innervates the skin of the ear and the skin below the ear. The marginal mandibular nerve is a branch of the facial nerve--it innervates the muscles of facial expression for the lower lip and chin.Rate this question:
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- 11.
A patient is unable to wink; what muscle is affected?
- A.
Frontalis
- B.
Levator palpebrae superioris
- C.
Orbicularis oculi
- D.
Superior tarsal
- E.
Zygomaticus major
Correct Answer
C. Orbicularis oculiExplanation
Orbicularis oculi is a muscle of facial expression that closes the eyelid for winking. It is innervated by the temporal and zygomatic branches of the facial nerve. Frontalis is the anterior belly of the epicranius muscle; it elevates the eyebrows and wrinkles the forehead. It is innervated by the temporal branches of the facial nerve (VII). Levator palpebrae superioris elevates the upper eyelid; it is innervated by the oculomotor nerve (III). The superior tarsal muscle is another muscle that elevates the eyelid, but it lifts the eyelid invoulntarily. It is innervated by the cervical sympathetic trunk; checking whether this muscle is functioning is a good test to see whether the cervical sympathetic trunk is intact. Finally, zygomaticus major is a muscle at corner of the mouth which elevates and draws the corner of the mouth laterally. It is innervated by the zygomatic and buccal branches of the facial nerve.Rate this question:
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- 12.
What structure lies deepest in the parotid gland?
- A.
External carotid artery
- B.
External jugular vein
- C.
Facial artery
- D.
Facial nerve
- E.
Retromandibular vein
Correct Answer
A. External carotid arteryExplanation
The facial nerve, retromandibular vein, and external carotid artery all course through the parotid gland. From superficial to deep, they are arranged nerve, vein, artery. So, the facial nerve would be the structure most likely to be injured by a superficial injury to the parotid gland, while the external carotid artery is somewhat protected, deep in the gland. The facial artery branches from the external carotid artery before the external carotid artery enters the parotid gland. The external jugular vein is a superficial vein on the lateral surface of the neck.Rate this question:
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- 13.
A deep laceration of the face in the middle of the parotid gland could affect the:
- A.
External jugular vein
- B.
Facial nerve
- C.
Glossopharyngeal nerve
- D.
Hypoglossal nerve
- E.
Lingual artery
Correct Answer
B. Facial nerveExplanation
The facial nerve travels through the parotid gland--it could become injured if there was a deep laceration through the parotid gland. Two other structures found within the parotid gland which might be damaged: the retromandibular vein and the external carotid artery. The nerve is the most superficial structure in the gland. Then, the vein is under the nerve, and the artery is the deepest structure in the gland.
The external jugular vein is a superficial structure on the lateral neck, so it's not really close to the parotid gland. The glossopharyngeal nerve is closely related to the stylopharyngeus muscle--it sweeps along the back of this muscle. It is not related to the parotid gland. The hypoglossal nerve travels laterally to the carotid vessels and then enters the floor of the mouth. This means that it travels inferior to the region of the parotid gland. Finally, the lingual artery is found in the floor of the mouth--far from the parotid gland!Rate this question:
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- 14.
Pain elicited from an infected facial wound is primarily conveyed by what nerve?
- A.
Facial
- B.
Great auricular
- C.
Hypoglossal
- D.
Transverse cervical
- E.
Trigeminal
Correct Answer
E. TrigeminalExplanation
The trigeminal nerve is the nerve that supplies sensory innervation to the skin of the face, so pain sensations will be carried through this nerve. It has 3 divisions. The ophthalmic division (V1) is a sensory nerve that passes through the superior orbital fissure and supplies sensory innervation to the eyeball, conjunctiva, nasal mucosa, medial portion of the nose, upper eyelid, forehead, and scalp. The maxillary division (V2) is a sensory nerve that provides sensory innervation to the cheek, upper lip, lateral portion of nose and lower eyelid. The mandibular division (V3) is a sensory and motor nerve--it supplies the lower lip and chin and the lateral portion of the cheek. V3 also provides motor innervation to the muscles of mastication, tensor veli palatini, mylohyoid, the anterior belly of the digastric, and tensor tympani.
The facial nerve does not provide sensory innervation to the skin of the face--it provides motor innervation to the muscles of facial expression. The great auricular nerve and transverse cervical nerve are branches of the cervical plexus. The great auricular nerve supplies the skin of the ear and the skin below the ear, while the transverse cervical nerve supplies the skin of the anterior neck. The hypoglossal nerve (CN XII) provides motor innervation to the muscles of the tongue.Rate this question:
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- 15.
Inability to close the lips relates to the action of which muscle?
- A.
Anterior belly of the digastric
- B.
Mylohyoid
- C.
Orbicularis oris
- D.
Platysma
- E.
Zygomaticus major
Correct Answer
C. Orbicularis orisExplanation
Orbicularis oris is a muscle of facial expression. It surrounds the lips, and allows for pursing of the lips. It is innervated by the buccal branch of the facial nerve. The anterior belly of the digastric and mylohyoid both help elevate the hyoid bone and depress the mandible. They are both innervated by a branch of the mandibular division of the trigeminal nerve (V3). Platysma and zygomaticus major are both muscles of facial expression, innervated by the facial nerve. Platysma draws the corners of the mouth down and aids in depressing the mandible; zygomaticus major elevates and draws the corners of the mouth laterally.Rate this question:
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- 16.
Which muscle will not be affected when the mandibular division of the trigeminal nerve (V3) is anesthetized?
- A.
Anterior belly of digastric
- B.
Buccinator
- C.
Medial pterygoid
- D.
Mylohyoid
- E.
Temporalis
Correct Answer
B. BuccinatorExplanation
Buccinator is innervated by the facial nerve (CN VII). It allows the corner of the mouth to be pulled laterally, and it allows the cheek to be pulled against the teeth. It is an important muscle for mastication, but it's not innervated by a branch of the mandibular division of the trigeminal nerve. (Note: the buccal brThe other muscles listed are all innervated by branches of V3. Mylohyoid and the anterior belly of the digastric are innervated by a small branch of V3. They both elevate the hyoid and depress the mandible. Medial pterygoid and temporalis are muscles of mastication, and the muscles of mastication are innervated by V3.anches of the facial nerve, which innervate buccinator, are not the same as the buccal nerve, a sensory branch of V3!)Rate this question:
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- 17.
A 38-year-old female patient complained of parotid pain that increased while eating. Intraoral examination detected some pus oozing from the parotid duct opening. What was the most likely anatomical reference that the physician considered to locate the parotid duct opening?
- A.
Mucosa of the sublingual caruncle behind the central incisor teeth
- B.
Mucosa of the cheek across the 2nd upper (maxillary) molar tooth
- C.
Mucosa of the floor of the mouth along the sublingual fold
- D.
Mucosa of the cheek across the 2nd lower (mandibular) molar tooth
Correct Answer
B. Mucosa of the cheek across the 2nd upper (maxillary) molar toothExplanation
The parotid duct opens into the vestibule of the mouth, draining into the mucosa of the cheek near the second upper molar tooth. The duct drains the parotid gland across the masseter and through the cheek. It passes through the buccinator muscle, and pours saliva into the vestibule of the mouth.
The sublingual caruncle is a small bump in the floor of the mouth, near the frenulum of the tongue. This is the site of the opening of the submandibular duct, which drains saliva from the submandibular gland. The mucosa along the sublingual fold contains many openings for the ducts coming from the sublingual gland. See Netter Plate 45 for a picture of all these ducts.Rate this question:
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- 18.
While recovering from a right facial paralysis, a 36-year-old female patient complained that food accumulated between the teeth and the cheek mucosa when chewing. The deficiency of which muscle was most likely the cause of the chewing problem?
- A.
Zygomaticus major
- B.
Orbicularis oris
- C.
Buccinator
- D.
Levator labii superioris
Correct Answer
B. Orbicularis orisExplanation
Although buccinator is innervated by the buccal branches of the facial nerve and not a branch of V3, the buccinator is an important muscle for mastication. The buccinator keeps the cheek taut so it is not folding over and becoming injured by chewing. It aids mastication by pulling the cheek against the molar teeth so that food does not keep collecting in the vestibule of the mouth. So, if this muscle was injured, the cheek could not press against the molar teeth, and food would fall between the teeth and cheek mucosa while chewing.
The other 3 muscles are all innervated by the facial nerve, but they are important for facial expression not mastication. Zygomaticus major elevates and draws the corners of the mouth laterally. Orbicularis oris purses the lips. Levator labii superioris elevates the upper lip.Rate this question:
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- 19.
The parotid space contains all EXCEPT:
- A.
External carotid artery
- B.
Facial nerve
- C.
Intraparotid lymph nodes
- D.
Medial pterygoid muscle
- E.
Retromandibular vein
Correct Answer
D. Medial pterygoid muscleExplanation
The medial pterygoid muscle is not in the parotid space. It serves as the anterior boundary of the parotid fossa. The other structures mentioned are all found within the parotid gland. The facial nerve, retromandibular vein, and external carotid artery all course through the parotid gland. From superficial to deep, they are arranged nerve, vein, artery. The intraparotid lymph nodes are found in the parotid gland also.Rate this question:
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- 20.
As a result of meningitis, a patient develops Bell's palsy. One of the symptoms was hyperacusis. What nerve was involved?
- A.
Facial
- B.
Glossopharyngeal
- C.
Oculomotor
- D.
Trigeminal
- E.
Vagus
Correct Answer
A. FacialExplanation
Bell's palsy is the paralysis of the facial nerve. This means that, on the affected side, the muscles of facial expression will appear flaccid, leading to a loss of expression. The patient will be unable to smile, lift their eyebrow, or close their eyelid on the affected side of the face. Besides the muscles of facial expression, the facial nerve also innervates stapedius, a small muscle in the ear. This muscle serves to dampen the vibrations of the tympanic membrane and quiet sounds. If the facial nerve is paralyzed, stapedius is paralyzed, too. This means that the ear can't dampen the vibrations from loud sounds, and the patient experiences hyperacusis.
It's important to remember the association between Bell's palsy and the facial nerve!Rate this question:
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- 21.
Frey's Syndrome is marked by profuse sweating over one cheek, temple, and surrounding areas of the face, precipitated by eating. The condition may be idiopathic, but often follows parotid surgery. The condition is attributable to abberant reinnervation, the redirection of autonomic fibers normally going to salivary glands being redirected to sweat glands. What is the source of the nerve fibers involved?
- A.
Facial
- B.
Glossopharyngeal
- C.
Oculomotor
- D.
Trigeminal
- E.
Vagus
Correct Answer
D. TrigeminalExplanation
Frey's syndrome is a condition in which the postganglionic parasympathetic nerves that are contained in the auriculotemporal nerve (which normally supply the parotid gland) are redirected toward the sweat glands overlying the parotid gland. This means that a patient with Frey's syndrome sweats in the area over the parotid gland while eating. Since the auriculotemporal nerve is a branch of V3, the nerve fibers involved in Frey's syndrome are from the trigeminal nerve.
The nerve fibers on the external carotid and internal carotid arteries are sympathetic fibers. Remember--sympathetic fibers create periarterial plexuses that travel with the vasculature to reach different targets around the body. However, the parotid gland is innervated parasympathetically, not sympathetically. The glossopharyngeal nerve contributes to the innervation of the parotid gland by supplying preganglionic parasympathetic fibers to the otic ganglia, by way of the lesser petrosal nerve. However, these fibers are not involved with Frey's syndrome--this condition involves the misdirection of the postganglionic parasympathetic fibers. Finally, the vagus is not involved with innervating the parotid gland.Rate this question:
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- 22.
While recovering from multiple dental extractions, an elderly man experienced a radiating pain affecting the lower eyelid, lateral side of the nose, upper lip and over the zygomatic and temporal areas on the left side. Which nerve is involved in the patient's perception of pain?
- A.
Facial
- B.
Opthalmic division of trigeminal
- C.
Glossopharyngeal
- D.
Mandibular division of trigeminal
- E.
Maxillary division of trigeminal
Correct Answer
E. Maxillary division of trigeminalExplanation
The trigeminal nerve is the nerve that supplies sensory innervation to the skin of the face. It has 3 divisions. The maxillary division of trigeminal (V2) is the one that's important for this case--it is a sensory branch of the trigeminal that provides innervation to the skin of the cheek, upper lip, lower eyelid, and the lateral portion of the nose. This is exactly the area that the patient feels pain, so it is the correct answer. The ophthalmic division (V1) is a sensory nerve that passes through the superior orbital fissure and supplies sensory innervation to the eyeball, conjunctiva, nasal mucosa, medial portion of the nose, upper eyelid, forehead, and scalp. The mandibular division (V3) is a sensory and motor nerve--it supplies skin of the lower lip, chin and lower jaw. V3 also provides motor innervation to the muscles of mastication, tensor veli palatini, mylohyoid, the anterior belly of the digastric, and tensor tympani.
The facial nerve innervates the muscles of facial expression, but it does not provide sensory innervation to the skin of the face. The glossopharyngeal nerve provides sensory innervation to the pharynx and sensory and taste innervation to the posterior 1/3 of the tongue. But, it does not innervate any skin on the face.Rate this question:
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- 23.
The facial muscle most responsible for moving the lips both upward and laterally to produce a smile is:
- A.
Buccinator
- B.
Levator anguli oris
- C.
Levator labii superioris
- D.
Platysma
- E.
Zygomaticus major
Correct Answer
E. Zygomaticus majorExplanation
Zygomaticus major is innervated by the zygomatic and buccal branches of the facial nerve. It elevates the corner of the mouth and draws it laterally. Remember zygomaticus major as the "smile" muscle! Levator anguli oris is close to the correct answer. This muscle, which is innervated by the facial nerve, elevates the corners of the mouth. However, zygomaticus major also draws the mouth laterally to produce a smile, so this answer is more correct.
The three other muscles are all innervated by branches of the facial nerve. Buccinator is innervated by the buccal branches of the facial nerve. It allows the cheek to be pulled taut against the molar teeth. Levator labii superioris is innervated by the buccal branch of the facial nerve--it pulls the lip upwards. Platysma is innervated by the cervical branches of the facial nerve. It draws the corners of the mouth downward and aids in depressing the mandible.Rate this question:
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