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44 Cards in this Set
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Loss of sensation from the temporal region and loss of secretory function of the parotid gland would be caused by interruption of which nerve?
Auriculotemporal Chorda tympani Deep temporal, posterior Facial Great auricular |
The correct answer is:
Auriculotemporal nerve 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. |
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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?
Buccal Infraorbital Mental Supratrochlear Zygomatic |
The correct answer is:
infraorbital 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. |
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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?
Buccinator Depressor anguli oris Levator anguli oris Levator labii superioris Stylohyoid |
The correct answer is:
depressor anguli oris 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. |
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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?
Buccinator Depressor anguli oris Levator anguli oris Levator labii superioris Stylohyoid |
The correct answer is:
depressor anguli oris 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. |
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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?
zygomatic (VII) buccal (VII) mental (V3) marginal mandibular (VII) infraorbital (V2) |
The correct answer is:
marginal mandibular 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. |
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Loss of sensation from the temporal region and loss of secretory function of the parotid gland would be caused by interruption of which nerve?
Auriculotemporal Chorda tympani Deep temporal, posterior Facial Great auricular |
The correct answer is:
Auriculotemporal nerve 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. |
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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?
Buccal Infraorbital Mental Supratrochlear Zygomatic |
The correct answer is:
infraorbital 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. |
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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?
Buccinator Depressor anguli oris Levator anguli oris Levator labii superioris Stylohyoid |
The correct answer is:
depressor anguli oris 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. |
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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?
Buccinator Depressor anguli oris Levator anguli oris Levator labii superioris Stylohyoid |
The correct answer is:
depressor anguli oris 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. |
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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?
zygomatic (VII) buccal (VII) mental (V3) marginal mandibular (VII) infraorbital (V2) |
The correct answer is:
marginal mandibular 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. |
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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?
maxillary (V2) greater auricular nerve ophthalmic (V1) mandibular (V3) facial (VII) |
The correct answer is:
ophthalmic (V1) 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. |
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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?
lingual superior thyroid facial ascending pharyngeal maxillary |
The correct answer is:
facial 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! |
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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?
inferior alveolar facial hypoglossal glossopharyngeal lingual |
The correct answer is:
facial 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. |
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Which nerve provides motor innervation to the buccinator muscle?
Auriculotemporal nerve Buccal branches of VII Buccal nerve Mandibular division of V Marginal mandibular nerve |
The correct answer is:
buccal branches of VII 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. |
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Which nerve provides cutaneous innervation to the skin of the angle of the mandible?
Auriculotemporal nerve Lesser petrosal nerve Buccal branches of VII Marginal mandibular nerve Great auricular nerve |
The correct answer is:
great auricular nerve 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. |
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Which nerve carries postganglionic parasympathetic fibers to the parotid gland?
Auriculotemporal nerve Lesser petrosal nerve Glossopharyngeal nerve Great auricular nerve Marginal mandibular nerve |
The correct answer is:
Auriculotemporal nerve 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. |
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A patient is unable to wink; what muscle is affected?
frontalis levator palpebrae superioris orbicularis oculi superior tarsal zygomaticus major |
The correct answer is:
orbicularis oculi 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. |
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What structure lies deepest in the parotid gland?
External carotid artery External jugular vein Facial artery Facial nerve Retromandibular vein |
The correct answer is:
external carotid artery 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. |
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A deep laceration of the face in the middle of the parotid gland could affect the:
External jugular vein Facial nerve Glossopharyngeal nerve Hypoglossal nerve Lingual artery |
The correct answer is:
facial nerve 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! |
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Pain elicited from an infected facial wound is primarily conveyed by what nerve?
Facial Great auricular Hypoglossal Transverse cervical Trigeminal |
The correct answer is:
trigeminal 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. |
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Inability to close the lips relates to the action of which muscle?
Anterior belly of the digastric Mylohyoid Orbicularis oris Platysma Zygomaticus major |
The correct answer is:
Orbicularis oris 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. |
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Which muscle will not be affected when the mandibular division of the trigeminal nerve (V3) is anesthetized?
Anterior belly of digastric Buccinator Medial pterygoid Mylohyoid Temporalis |
The correct answer is:
Buccinator 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 branches of the facial nerve, which innervate buccinator, are not the same as the buccal nerve, a sensory branch of V3!) The 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. |
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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?
Mucosa of the sublingual caruncle behind the central incisor teeth Mucosa of the cheek across the 2nd upper (maxillary) molar tooth Mucosa of the floor of the mouth along the sublingual fold Mucosa of the cheek across the 2nd lower (mandibular) molar tooth |
The correct answer is:
Mucosa of the cheek across the 2nd upper (maxillary) molar tooth 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. |
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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?
Zygomaticus major Orbicularis oris Buccinator Levator labii superioris |
The correct answer is:
Buccinator 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. |
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The parotid space contains all EXCEPT:
External carotid artery Facial nerve Intraparotid lymph nodes Medial pterygoid muscle Retromandibular vein |
The correct answer is:
Medial pterygoid muscle 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. |
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As a result of meningitis, a patient develops Bell's palsy. One of the symptoms was hyperacusis. What nerve was involved?
Facial Glossopharyngeal Oculomotor Trigeminal Vagus |
The correct answer is:
Facial 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! |
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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?
Facial Glossopharyngeal Oculomotor Trigeminal Vagus |
The correct answer is:
Trigeminal 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. |
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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?
Facial Opthalmic division of trigeminal Glossopharyngeal Mandibular division of trigeminal Maxillary division of trigeminal |
The correct answer is:
Maxillary division of trigeminal 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. |
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The facial muscle most responsible for moving the lips both upward and laterally to produce a smile is:
Buccinator Levator anguli oris Levator labii superioris Platysma Zygomaticus major |
The correct answer is:
Zygomaticus major 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. |
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You are testing the extraocular muscles and their innervation in a patient who periodically experiences double vision. When you ask him to turn his right eye inward toward his nose and look downward he is able to look inward, but not down. Which nerve is most likely involved?
Abducens Nasociliary Oculomotor, inferior division Oculomotor, superior division Trochlear |
The correct answer is:
trochlear To understand this question, you need to understand how the motions of the eye are tested. Since the actions of the extraocular muscles are complex, it is necessary to turn the eye to a position where a single action of each muscle predominates when evaluating the individual muscles. A key principle for muscle testing is: if a muscle has two actions and you perform one of those two, then it can't perform its other action. Superior and inferior recti turn the eye in and up or in and down. Superior and inferior oblique turn the eye out and down or out and up. So, if you turn your eye in (with the superior and inferior rectus as well as medial rectus), then only superior and inferior oblique can move the eye down or up (because the superior and inferior recti are already shortened by turning the eye in - they can't shorten any more). Similarly, if you turn the gaze out (with the obliques and lateral rectus) then only superior and inferior rectus can turn the eye up or down. In this case, the patient has the eye turned inward, so the doctor must be testing the oblique muscles. The superior oblique muscle is the muscle that lowers the eye when it is turned inward. Since the patient can't do this, the superior oblique must not be functioning, and this muscle is innervated by the trochlear nerve. Abducens (CN VI) innervates the lateral rectus muscle, which is not involved in the eye test. The nasociliary nerve comes from the ophthalmic division of the trigeminal nerve (V1). It is a sensory nerve to the eyeball that also carries some sympathetic fibers. The inferior division of the oculomotor nerve innervates inferior rectus, inferior oblique, and medial rectus. All of these muscles appear to be functioning. Finally, the superior division of the oculomotor nerve innervates levator palpebrae superioris and superior rectus. These are not the muscles that appear to be malfunctioning. |
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The outermost layer of the optic nerve sheath is a continuation of the:
Arachnoid membrane Meningeal dura Periosteal dura Pia mater Retina |
The correct answer is:
meningeal dura The optic nerve comes off the base of the brain and passes through the optic canal. As it leaves the brain, it still retains all of the meningeal layer coverings. So, it is covered by meningeal dura, arachnoid membrane, and pia mater. This is significant, because an increase in intracranial pressure will increase the pressure in the subarachnoid space. This may squeeze the optic nerve and make the optic nerve bulge into the eye, a condition known as papilledema. The periosteal dura is the layer of periosteum covering the internal surface of the calvaria. The retina is the inner layer of the eyeball which receives and absorbs visual light rays. |
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The inner lining of the eyelid is called the:
Orbital septum Palpebral conjunctiva Periorbita Sclera Tarsal plate |
The correct answer is: palpebral conjunctiva
The palpebral conjunctiva is the thin membrane that lines the eyelid. It is continuous with the bulbar conjunctiva which lines the eyeball. The orbital septum is a weak membrane that spans from the tarsal plates to the margins of the orbit where it becomes continuous with the periosteum. It contains orbital fat and can limit the spread of infection in the orbit. The periorbita is the periosteum lining covering the bones forming the orbit. The sclera is the outer fibrous layer of the eyeball. Finally, the tarsal plate is a thin, cardboard-like layer of connective tissue in the eyelids which forms the "skeleton" of the eyelids. |
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What would the examining physician notice in the eye of a person who has taken a sympathetic blocking agent?
Exophthalmos and dilated iris Enophthalmos and dry eye Dry eye and inability to accommodate for reading Wide open eyelids and loss of depth perception Ptosis and miosis (pin-point pupil) |
The correct answer is:
Ptosis and miosis (pin-point iris) Start this question out by thinking about what a sympathetic blocker would do to the pupil of the eye. Since sympathetic nerves allow the pupil to dilate, a sympathetic blocker would stop the eye from dilating and make the pupil constrict. Now think about the other issues. First, remember that sympathetic nerves innervate the superior tarsal muscle, which elevates the eyelids. If there is a problem with the regional sympathetics (as is the case with Horner's syndrome), the superior tarsal muscle will be paralyzed, and the eyelid will droop (ptosis). If the sympathetic nervous system is inhibited, sweating will cease, and you will observe the eye sinking back into the orbit. Accomodation is not mediated by the sympathetic system; accomodation is a function of parasympathetic nerve so this should not be affected. Finally, the lacrimal gland is innervated by parasympathetics, so there should not be a major change in eye secretions after a sympathetic blocker. Putting all of these factors together, answer choice E is the only one that fits! |
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You are examining a patient who has a pituitary tumor involving the cavernous sinus. While doing a preliminary eye exam, you suspect the right abducens nerve of the patient has been damaged by the tumor. In which direction would you have the patient turn his right eye to confirm the defect?
Inward Outward Downward Down and out Down and in Upward Up and out Up and in |
The correct answer is:
outward To understand this question, you need to understand how the motions of the eye are tested. Since the actions of the extraocular muscles are complex, it is necessary to turn the eye to a position where a single action of each muscle predominates when evaluating the individual muscles. For the superior and inferior recti, turning the eye outward (abduction) by approximately 25 degrees places the superior rectus in position to raise the eye and the inferior rectus to lower the eye. Similarly, turning the eye inward (adduction) approximately 50 degrees places the inferior oblique in position to raise the eye and the superior oblique to lower the eye. The medial and lateral recti may be checked while the eye is staring straight ahead since they have simple planar actions. In this case, you're interested in testing an "easy" muscle. Since the lesion appears to be in the abducens, which innervates the lateral rectus muscle, you could just ask the patient to turn the eye outward. If the patient could not do this, it would confirm that there was a lesion in the abducens nerve, since the muscle responsible for lateral movement of the eye would be paralyzed. Also remember--a tumor in the cavernous sinus could affect many nerves. The oculomotor nerve (CN III), trochlear (CN IV), ophthalmic division of trigeminal (CN V1), and abducens (CN VI) all pass through the cavernous sinus. |
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You have a patient with a drooping right eyelid. You suspect Horner's syndrome. Which of the following signs on the right side would confirm this diagnosis?
Constricted pupil Dry eye (lack of tears) Exophthalmos Pale, blanched face Sweaty face |
The correct answer is:
constricted pupil Horner's syndrome is a disorder involving damage to the sympathetic trunk in the neck. This means that the sympathetics of the head will be disrupted. This causes a variety of very characteristic symptoms, including a constricted pupil. Remember--sympathetic nerves innervate the dilator pupillae muscle. This muscle allows the eye to dilate. If these sympathetic nerves are lost, the pupil will contract. Several of the other listed symptoms are the opposite of what you would expect with Horner's syndrome. Exophthalmos is the protrusion of the eye, but in Horner's syndome the eye sinks in, possibly due to the paralysis of a smooth muscle in the floor of the orbit. The face does not become blanched and sweaty with Horner's syndrome--instead, it becomes red and dry. Without the sympathetic nerve supply, the vasculature of the face cannot constrict. So, the arterioles in the patient's face are vasodilated, making the face red. Sympathetic nerves also innervate sweat glands; if these nerves are interrupted, the patient will not sweat and the face will appear very dry. Finally, the lacrimal gland is innervated by parasympathetics, not sympathetics. So, Horner's syndrome should produce no appreciable changes in tearing. Make sure to know the different symptoms and signs of Horner's syndrome! |
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Following endarterectomy on the right common carotid, a patient is found to be blind in the right eye. It appears that a small thrombus embolized during surgery and lodged in the artery supplying the optic nerve. What artery would be blocked?
Central artery of the retina Infraorbital Lacrimal Nasociliary Supraorbital |
The correct answer is:
Central artery of the retina The central artery of the retina is a branch of the ophthalmic artery. It is the sole blood supply to the retina; it has no significant collateral circulation and blockage of this vessel leads to blindness. The branches of this artery are what you view during a fundoscopic exam. The infraorbital artery is a branch of the maxillary artery. It comes through the infraorbital foramen, inferior to the eye. It supplies the maxillary sinus, the maxillary incisors, canine and premolar teeth, and the skin of the cheek below the orbit. The supraorbital artery is another branch of the ophthalmic artery. It comes through the supraorbital foramen or notch and supplies blood to the muscles, skin and fascia of the forehead. The lacrimal artery is a branch of the ophthalmic artery that supplies the lacrimal gland. The nasociliary artery doesn't exist, but there is a nasociliary nerve (the third and lowest branch of the ophthalmic division) that travels with the continuation of the ophthalmic artery. |
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You are asked to check the integrity of the trochlear nerve in the right eye of a patient. Starting with the eyes directed straight ahead, you would have the patient look:
Inward, toward the nose and downward Inward, toward the nose and upward Toward the nose in a horizontal plane Laterally in a horizontal plane Outward, away from the nose and downward Outward, away from the nose and upward |
The correct answer is:
Inward, toward the nose and downward To understand this question, you need to understand how the motions of the eye are tested. Since the actions of the extraocular muscles are complex, it is necessary to turn the eye to a position where a single action of each muscle predominates when evaluating the individual muscles. To test the superior and inferior recti, a patient needs to turn the eye outward approximately 25 degrees. At this postion, the superior rectus will simply act to raise the eye, and the inferior rectus will lower the eye. To test the superior and inferior obliques, a patient needs to turn the eye inward approximately 50 degrees. When the eye is in this position, the superior oblique muscle will act to lower the eye, and the inferior oblique will act to raise the eye. So, now that you understand how to the test the eye, you have to decide which muscle is innervated by the trochlear nerve. And that's the superior oblique. So, to test this muscle, the eye needs to turn inward (toward the nose) and downward. What nerves innervate the other muscles? The abducens nerve (CN VI) innervates the lateral rectus muscle. The oculomotor nerve (CN III) innervates the superior rectus, inferior rectus, medial rectus, and inferior oblique muscles. |
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The ducts of the lacrimal gland open into the:
Superior fornix of the conjunctiva Inferior fornix of the conjunctiva Lacrimal puncta Lacrimal canaliculi Lacrimal lake |
The correct answer is:
Superior fornix of the conjunctiva Lacrimal fluid is produced by the lacrimal gland, which lies in a fossa in the superolateral part of each orbit. The fluid from this gland enters the conjunctival sac through up to 12 lacrimal ducts that open into the superior conjunctival fornix. The tears then flow to the medial angle of the eye and collect in the lacrimal lake. The lacrimal papilla are small elevations on the eyelids, found near the lacrimal lake. These papillae have small openings called the lacrimal puncta; tears flow from the lacrimal lake into these puncta. From there, the lacrimal fluid goes into small canniliculi which drain the fluid into the lacrimal sac. The lacrimal sac continues on as the nasolacrimal duct and drains tears into the inferior nasal meatus. Take a look at Netter Plate 77 and try to follow the path of tears from the lacrimal gland to the inferior meatus! |
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Starting from a position gazing straight ahead, to direct the gaze downward, the inferior rectus muscle must be active along with the:
Superior oblique Inferior oblique Medial rectus Lateral rectus Superior rectus |
The correct answer is:
Superior Oblique The inferior rectus muscle depresses the eye and medially rotates it. So, to direct the gaze downward, you want to find a muscle that will depress the eye while counterbalancing the medial rotation with lateral rotation. And, the superior oblique, innervated by the trochlear nerve (CN IV), does just that--it depresses the eye while laterally rotating it. The inferior oblique muscle laterally rotates the eye and elevates the eye. The medial rectus adducts the eye--it does not raise or lower the eye. The lateral rectus abducts the eye--it also does not raise or lower the eye. Finally, the superior rectus elevates the eye and draws it medially. |
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During a physical examination it is noted that a patient has ptosis. What muscle must be paralyzed?
Orbicularis oculi, lacrimal part Orbicularis oculi, palpebral part Stapedius Superior oblique Superior tarsal (smooth muscle portion of levator palpebrae) |
The correct answer is:
Superior tarsal The superior tarsal muscle is a smooth muscle which is sympathetically innervated. It is an involuntary muscle that elevates the eyelid. It is innervated by the cervical sympathetic trunk, and this muscle's functioning provides a good indication of the integrity of the cervical sympathetic trunk. If the cervical sympathetic trunk has been damaged, a patient will have ptosis, a droopy eyelid. Orbicularis oculi is innervated by the facial nerve. If this muscle is paralyzed, the problem won't be a droopy eyelid--instead, the patient won't be able to close the eyelid. This is why patients with Bell's palsy are prescribed lubricating eye drops--if they can't close the eyelid, they may be at risk for corneal irritation. Stapedius is another muscle innervated by the facial nerve -- it serves to dampen the vibrations of the stapes and the tympanic membrane. Finally, the superior oblique muscle depresses the eyeball and turns it laterally. It does not affect the eyelid. |
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The extraocular muscle that does not originate at or near the apex of the orbit is the :
Inferior oblique Inferior rectus Levator palpebrae superioris Superior oblique Superior rectus |
The correct answer is:
Inferior oblique The inferior oblique muscle does not originate at the apex of the orbit. It takes origin from the floor of the orbit, lateral to the lacrimal groove. The inferior rectus and superior rectus muscles take origin from the common tendinous ring at the apex of the orbit. The levator palpebrae superioris takes origin from the apex of the orbit above the optic canal. The superior oblique muscle takes origin from the apex of the orbit, above the optic canal. For a picture of this, see Netter Plate 79. |
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An adolescent boy suffers from severe acne. As is often the case he frequently squeezed the pimples on his face. He subsequently develops a fever and deteriorates into a confused mental state and drowsiness. He is taken to his physician and after several tests a diagnosis of cavernous sinus infection and thrombosis is made. The route of entry to the cavernous sinus from the face was most likely the:
Carotid artery Mastoid emissary vein Middle meningeal artery Ophthalmic vein Parietal emissary vein |
The correct answer is:
Ophthalmic vein The ophthalmic veins are continuous with the facial vein and the pterygoid plexus of veins. These veins drain the face toward the cavernous sinus. They are valveless, so infections from the face can drain into the cavernous sinus. Besides causing fever and confusion, thrombotic congestion and edema in the cavernous sinus can compress the nerves that traverse that space to exit through the superior orbital fissure(CN III, CN IV, CN V1, and CN VI). This can affect the function of the ocular muscles, so one symptom of a cavernous sinus infection might be an inability to perform different eye movements. The carotid artery and middle meningeal artery would not be the source of the infections. Infections do not tend to enter through arterial circulation. Remember--the common carotid is the major source of blood to the head and neck, and the middle meningeal artery is the branch of the maxillary artery that supplies blood to the dura. The emissary veins are valveless veins of the scalp. These veins can carry blood from the scalp to the dural venous sinuses or in the reverse direction depending on blood pressure. These veins may carry infectious materials from the scalp into the dural venous sinuses, but they are not important for carrying infections to the cavernous sinus. |
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If a person looking inward towards their nose is unable to look down, which nerve may be injured?
Abducens (CN VI) Inferior division of oculomotor (III) Optic (II) Superior division of oculomotor (III) Trochlear (IV) |
The correct answer is:
Trochlear (IV) To understand this question, you need to understand how to evaluate the muscles of the eye. Since the actions of the extraocular muscles are complex, it is necessary to turn the eye to a position where a single action of each muscle predominates. To isolate the superior and inferior recti, the patient needs to turn the eye outward by approximately 25 degrees. This places the superior rectus in position to raise the eye and the inferior rectus in position to lower the eye. Turning the eye inward approximately 50 degrees places the inferior oblique in position to raise the eye and the superior oblique in position to lower the eye. The medial and lateral recti are the easy muscles -- they may be checked while the eye is staring straight ahead since they have simple planar actions So, this patient is looking inward, which means that the obliques are being tested. The patient can't look downward, which shows that the superior oblique is not functional. This is the only muscle innervated by the trochlear nerve (CN IV). Abducens (CN VI) innervates the lateral rectus muscle, which is tested by asking the patient to move the eye outward. The inferior division of the oculomotor nerve innervates inferior rectus, inferior oblique, and medial rectus. The superior branch of the oculomotor nerve innervates levator palpebrae superioris and superior rectus muscles. Finally, the optic nerve (CN II) provides the special sense of vision, and it is not tested in the eye-movement tests. Are you getting the idea that you really need to know about testing the eye muscles? Take the time and really understand this concept--you'll be glad that you did! |
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If a person is taking a sympathetic blocking agent, what would you notice in her or his eyes?
Dry eyes and inability to accommodate for reading Enophthalmos and teary eyes (III) Exophthalmos and dilated pupil Ptosis and constricted pupil Wide open eyes and loss of depth perception (IV) |
The correct answer is:
Ptosis and constricted pupil To understand this question, it's important to look at all the different choices and determine which ones fit with a sympathetic block. First, the lacrimal gland is innervated parasympathetically, so a sympathetic blocker should have no effect on eye secretions. Accomodation is also a function of the parasympathetic nervous system; it should not be altered by a sympathetic blocker. Enophthalmos is the name for the eye sinking into its orbit. A sympathetic block does cause enophthalmos, due to the paralysis of a smooth muscle in the floor of the orbit. Exophthalmos is the opposite of enophthalmos--it is the protrusion of the eye from the orbit. You would not see exophthalmos with a sympathetic blockade. Sympathetic nerves allow the eye to dilate--if you blocked these nerves, the eye would constrict. A sympathetic blocker would also cause ptosis--it would paralyze the superior tarsal muscle, which holds the lids up involuntarily and receives sympathetic innervation. Finally, the sympathetic blocker should not affect depth perception. If you put all of these things together, answer choice D is the correct one. If it helps to remember, taking a sympathetic blocking agent will lead to similar symptoms in the head and neck as Horner's syndrome, a disease characterized by a loss of sympathetic innervation to the head and neck. |
