Question 1: Answer: D
A. Angular artery
Explanation: The angular artery is the terminal portion of the facial artery located between the nose and the medial corner of the eye.
B. Superior labial artery
Explanation: The superior labial artery is a branch of the facial artery that supplies blood to the upper lip region.
C. Transverse facial artery
Explanation: The transverse facial artery is a branch of the superior temporal artery that supplies blood to the lateral region of the face just below the zygomatic arch.
D. Mental artery
Explanation: The mental artery is located immediately below the lower lip exiting from the mental protuberance of the mandible through the mental foramen. The mental artery supplies the “chin” and is correct.
E. Buccal artery
Explanation: The buccal artery is a branch of the maxillary artery and perforates the buccinator muscles bilaterally in the cheek region.
Question 2: Answer: C
A. Ethmoid sinuses (ethmoid air cells)
Explanation: The ethmoid sinuses are small, thin-walled cavities (3-18 per side) that are located within the ethmoid bones between the upper nasal cavity and the orbit. Infection here would not cause pain and pressure above the eyebrows in the forehead.
B. Maxillary sinus
Explanation: The maxillary sinuses are bilateral structures located in the maxilla bone above the superior molars and below the orbits. Infection here would not cause pain and pressure above the eyebrows in the forehead.
C. Frontal sinus
Explanation: The frontal sinuses are paired structures located within the frontal bone above the medial portions of the eyebrows. Infection of these sinuses often causes pain and a pressure buildup that is felt in the glabella and supraorbital regions of the frontal bone.
D. Sphenoid sinus
Explanation: The sphenoid sinus is a paired structure located posterior to the upper nasal cavity near important structures like the cavernous sinus and the pituitary gland.
E. Spheno-ethmoidal recess
Explanation: The spheno-ethmoidal recess is not considered one of the paranasal sinuses; rather, it is a nasal cavity region that drains the sphenoid sinus.
Question 3: Answer: E
A. Loss of sensation of the upper lip
Explanation: Sensation of the upper lip is provided by the maxillary division (V2) of the trigeminal nerve. Damage to the mandibular division (V3) of the trigeminal nerve would not affect sensation here.
B. Ability to swallow is diminished
Explanation: The ability to swallow is mainly provided by the innervation of pharyngeal musculature by the vagus nerve (CN X) and the glossopharyngeal nerve (CN IX). Damage to the mandibular division (V3) of the trigeminal nerve would not affect the ability to swallow.
C. Ability to forcefully close the eyes is diminished
Explanation: The ability to forcefully close the eyes is provided by the facial nerve (CN VII). Damage to the mandibular division (V3) of the trigeminal nerve would not affect the ability to forcefully close the eyes.
D. Ability to raise the corner of the mouth is diminished
Explanation: The ability to raise the corner of the mouth is provided by the zygomaticus muscles, which are innervated by the facial nerve (CN VII). Damage to the mandibular division (V3) of the trigeminal nerve would not affect the ability to raise the corner of the mouth.
E. Loss of sensation in the tip of the tongue
Explanation: Along with providing sensation to the lower lip, the mandibular division (V3) of the trigeminal nerve also provides sensation to the mandibular gums and teeth, as well as the anterior surface of the tongue via the lingual nerve branch. Thus, damage to V3 would cause loss of sensation in the tip of the tongue.
Question 4: Answer: C
A. Alveolar cells, milk production
Explanation: The alveolar cells do indeed produce the milk that is sent down the lactiferous ducts, but oxytocin does not act on these cells. Prolactin is the hormone responsible for milk production and directly affects these cells.
B. Myoepithelial cells, muscle relaxation
Explanation: The myoepithelial cells that line the lactiferous ducts are acted upon by oxytocin, but it does not cause muscle relaxation.
C. Myoepithelial cells, muscle contraction
Explanation: The myoepithelial cells that line the lactiferous ducts are acted upon by oxytocin that induces a contraction of the myoepithelial cell to push the milk along the ducts toward the nipple.
D. Alveolar cells, muscle relaxation
Explanation: The alveolar cells are responsible for milk production and do not have any ability to contract or relax.
E. Myoepithelial cells, milk production
Explanation: The myoepithelial cells do no participate in milk production.
Question 5: Answer: D
A. Lateral crico-arytenoids
Explanation: The lateral crico-arytenoid muscles are the main adductors of the vocal folds. They are antagonized by the posterior crico-arytenoids, which abduct the vocal folds. Paralysis of the lateral crico-arytenoid muscles would not prevent abduction of the vocal folds.
B. Thyro-arytenoids
Explanation: The thyro-arytenoid muscles lie parallel to the vocal folds, extending anterior to posterior from the thyroid cartilage to the arytenoid cartilage. They serve to pull these two structures together, reducing tension in the vocal folds, but they do not participate in abduction or adduction.
C. Transverse arytenoid
Explanation: The transverse arytenoid muscle, located on the posterior surface of the arytenoid cartilages, participates in vocal cord adduction, not abduction.
D. Posterior crico-arytenoids
Explanation: The posterior crico-arytenoids are the only intrinsic laryngeal muscles that can abduct the vocal cords. If these muscles are paralyzed, the patient’s vocal cords would remain adducted, which would prevent air from passing down into the lungs.
E. Cricothyroids
Explanation: The cricothyroid muscles are the only tensor muscle of the vocal cords. It aids in phonation by tensing the vocal cords, but does not participate in abduction or adduction.
Question 6: Answer: A
A. Corti ganglion
Explanation: The Corti ganglion, or spiral ganglion, is a group of nerve cells that convey the sense of hearing from sound sensory input from the individual organs of Corti within the cochlea. Cell loss in this ganglion would contribute to hearing loss.
B. Pterygopalatine ganglion
Explanation: The pterygopalatine ganglion is a parasympathetic ganglion that mainly controls the lacrimal glands and the nasal mucosa and is not involved in auditory input processing.
C. Vestibular (Scarpa) ganglion
Explanation: The vestibular ganglion contains nerve cells that receive input from the hair cells of the crista ampullaris and maculae. These vestibular end organs play a vital role in balance, possibly pointing to the reason for this patient’s dizziness issues but not his hearing problems.
D. Superior cervical ganglion
Explanation: The superior cervical ganglion is a sympathetic ganglion that supplies sympathetic to structures within the head including the pineal gland, cranial blood vessels, choroid plexus, salivary and lacrimal glands, and the eye. It does not participate in the hearing pathway.
E. Otic ganglion
Explanation: The otic ganglion is a parasympathetic ganglion that is responsible for the innervation of the parotid gland for salivation but is not involved in the hearing sensory pathway.
Question 7: Answer: C
A. Superior to the maxillary artery
Explanation: The maxillary artery is one of the terminal branches of the external carotid artery. Occlusion of this artery would not explain the symptoms of blood loss of branches inferior to this vessel, specifically the facial, occipital, posterior auricular, and superficial temporal arteries.
B. At the level of the ascending pharyngeal artery
Explanation: An occlusion of the external carotid artery at the level of the ascending pharyngeal artery would also affect the lingual artery, which would cause symptoms of decreased blood flow the tongue.
C. Just below the facial artery
Explanation: An occlusion of the external carotid artery just below the level of the facial artery would decrease blood flow to all of the downstream branches including occipital, posterior auricular, maxillary, and superficial temporal arteries, which coincide with the areas of symptomology.
D. At the level of the occipital artery
Explanation: An occlusion of the external carotid artery at the level of the facial artery would decrease blood flow to all of the downstream branches described by the symptoms except the facial artery.
E. At the bifurcation of the common carotid artery
Explanation: An occlusion at the level of the common carotid artery bifurcation would occlude all branches off the external carotid artery, including the superior thyroid, ascending pharyngeal, and lingual arteries, which show no symptoms of occlusion in this patient.
Question 8: Answer: D
A. Viewing objects at a distance
Explanation: To view distant objects, the ciliary muscle must relax, which stretches the suspensory ligaments and flattens the lens, providing an optimal focal point for distant objects. Cycloplegia patients would have no issues seeing objects at a distance.
B. Abducting the eye
Explanation: Abduction of the eye involves the lateral rectus muscle, which is not affected in ciliary muscle paralysis.
C. Abducting and depressing the eye
Explanation: Abducting and depressing the eye describes the action of the superior rectus muscle, which is not affected in ciliary muscle paralysis.
D. Viewing close objects
Explanation: To view close objects, the ciliary muscle must contract, creating slack in the suspensory ligaments. This results in a more rounded shape to the lens, which is necessary to view close objects. Paralysis in the ciliary muscle would prevent this from occurring.
E. Adducting the eye
Explanation: Adducting the eye is provided by the medial rectus muscle, which is not affected by ciliary muscle paralysis.
Question 9: Answer: C
A. Mandible deviates to the left when the mouth is opened
Explanation: A deviation of the mandible when the mouth is opened would indicate a paralysis in the lateral pterygoid muscle on the ipsilateral side. The lateral pterygoid muscle is innervated by the trigeminal nerve, which is not affected in this patient.
B. Right corner of the mouth droops when smiling
Explanation: The corners of the mouth are raised by the zygomaticus major muscle, which is innervated by the facial nerve. A lesion in the left facial motor nucleus would cause paralysis of the facial muscles on the same side as the injury; thus the left side of the mouth would droop in the patient instead of the right.
C. Left corner of the mouth droops when smiling
Explanation: The corners of the mouth are raised by the zygomaticus major muscle, which is innervated by the facial nerve. A lesion in the left facial motor nucleus would cause paralysis of the facial muscles on the same side as the injury, as is the case in this patient.
D. Unable to wrinkle the forehead on the right side
Explanation: The temporal branch of the facial nerve receives contribution from both the left and right facial motor nuclei; thus damage to only one of the nuclei would not eliminate the ability to wrinkle the forehead on either side.
E. Mandible deviates to the right when the mouth is opened
Explanation: A deviation of the mandible when the mouth is opened would indicate a paralysis in the lateral pterygoid muscle on the ipsilateral side. The lateral pterygoid muscle is innervated by the trigeminal nerve, which is not affected in this patient.
Question 10: Answer: B
A. Gag reflex
Explanation: The gag reflex is elicited by touching the back of the patient’s mouth with a tongue depressor, testing cranial nerves IX and X. Both of these nerves originate in the medulla.
B. Corneal reflex
Explanation: The corneal reflex (also known as the blink reflex) tests the pons by stimulating cranial nerves V and VII, both of which originate in the pons. The reflex is elicited by lightly touching the cornea with a foreign object, which causes a protective eye-closing reflex.
C. Vestibulocochlear reflex
Explanation: The vestibuloocular reflex is a reflex that stabilizes images on the retina during while the head is moving. The reflex stimulates cranial nerve VIII, as well as the nerves to the extra-ocular muscles (cranial nerves III, IV, and VI), all of which do not originate in the pons.
D. Accommodation reflex
Explanation: The accommodation reflex tests coordinated changes in convergence of the eye when switching from focus on close up and far away objects. This reflex is dependent on cranial nerves II and III, neither of which originates in the pons.
E. Pupillary light reflex
Explanation: The pupillary light reflex tests the ability of the pupil to constrict in the presence of direct light. This reflex tests cranial nerves II and III, neither of which originates in the pons.