Block 5 Anat Skul Cranial Fossa Face Scalp Ta's W Expl
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- 1.
________ exits the skull through the internal acoustic meatus ; however, only _______ exits the skull through the stylomastoid foramen .
- A.
Facial nerve only , Facial nerve only
- B.
Vestibulocochlear nerve only , vestibulocochlear nerve only
- C.
Both facial and vestibulocochlear nerves , Both facial and vestibulocochlear nerves
- D.
Both facial and vestibulocochlear nerves, Only facial nerve
- E.
Both facial and vestibulocochlear nerves , Only vestubulocochlear nerve
Correct Answer
D. Both facial and vestibulocochlear nerves, Only facial nerveExplanation
Both vestibulocochlear & facial nerve enter the internal acoustic meatus. The vestibulocochlear nerve enters the internal acoustic meatus splits into its respective branches terminating in the inner ear. The facial nerve enters the internal acoustic meatus and then exits the skull through the stylomastoid forman to travel to the anterior aspect of the skull and provide innervation to the facial muscles.Rate this question:
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- 2.
A patient arrives at your office following a disastrous work injury at the metal factory. A sharp object is seen piercing the patient's left eye and radiological imaging demonstrates complete damage to the structures found within the left optic canal. Which of the following have most likely been damaged?
- A.
Superior ophthalmic vein
- B.
Inferior ophthalmic vein
- C.
Cavernous sinus
- D.
Ophthalmic artery
- E.
CN I
- F.
CN V: V2 Branch
- G.
Ophthalmic nerve
Correct Answer
D. Ophthalmic arteryExplanation
The optic canal carries both the optic nerve and ophthalmic artery. A and B are incorrect because these structures pass through the superior orbital fissure and Foramen Rotundum, respectively. CN I is the olfactory nerve and passes through the cribriform plate of the ethmoid bone and is not found in this region. CNV: V2 is the maxillary nerve and passes through the inferior orbital fissure. The ophthalmic nerve is also known as V1 and travels through the superior orbital fissure. The cavernous sinus is found within the skull cavity near the entry to the optic canal and though it may have been damaged if the metal traveled far enough, the ophthalmic artery would have certainly been damaged first and is therefore a better answer.Rate this question:
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- 3.
A 65 year old woman had optic nerve damage. An MRI revealed that the foramen that Cranial Nerve II goes through is damaged. Which one of the following is also most likely damaged?
- A.
Facial Nerve
- B.
Ophthalmic Division of Trigeminal Nerve
- C.
Mandibular Division of Trigeminal Nerve
- D.
Ophthalmic Artery
- E.
Facial Artery
Correct Answer
D. Ophthalmic ArteryExplanation
The Optic nerve (CN II) and the Ophthalmic artery both travel through the optic canal.Rate this question:
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- 4.
What structures pass through the superior orbital fissure?
- A.
Cranial nerves III, IV, VI , VI, and Middle Meningeal artery
- B.
Cranial nerves III, IV, VI , VI, and Ophthalmic artery
- C.
Cranial nerves III, IV, VI,2,3 , VI
- D.
Cranial nerves III, IV, VI , VI, and Ophthalmic vein
Correct Answer
D. Cranial nerves III, IV, VI , VI, and Ophthalmic veinExplanation
The ophthalmic artery along with the Optic nerve passes through the Optic Canal. The middle meningeal artery passes through Foramen Spinosum. The maxillary branch of the Trigeminal nerve passes through Foramen Rotundum and the mandibular branch passes through Foramen Ovale.Rate this question:
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- 5.
Mr. Balkaran, 16-year-old boy with severe acne, develops an upper eyelid infection. As a good physician, you are very concerned about spread of the infection to the dural venous sinus. With which of the following dural venous sinuses does the superior ophthalmic vein directly communicate?
- A.
Occipital sinus
- B.
Sigmoid sinus
- C.
Straight sinus
- D.
Cavernous sinus
- E.
Superior petrosal sinus
Correct Answer
D. Cavernous sinusExplanation
The superior ophthalmic vein passes through the superior orbital fissure and flows into the cavernous sinus. Because emissary veins lack valves, blood flow in the superior ophthalmic vein can occur in either direction. The cavernous sinus is lateral to the pituitary gland and contains CN III, IV, V1, V2, VI and the internal carotid artery. Infection the cavernous sinus could infect any of them.Rate this question:
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- 6.
Mr. Ringmy, a 34 year old salesman, presents with a drooping face and forehead consistent with Bell’s palsy. It is found on radiological examination that there is a tumor that compresses the cranial nerve responsible for these finding at the location it exits the skull. What is the location of the tumor?
- A.
Foramen rotundum
- B.
Foramen ovale
- C.
Jugular foramen
- D.
External acoustic foramen
- E.
Stylomastoid foramen
Correct Answer
E. Stylomastoid foramenExplanation
The facial nerve exits the stylomastoid foramen to innervate the muscles of facial expression(the taste fibers do not exit through the stylomastoid foramen. They exit before this foramen.). Without knowing there was a tumor, Bell’s palsy would still indicate a LMN lesion. Interestingly Bell’s palsy is often idiopathic, but can also be caused by HIV, Lyme disease, a middle ear infection, and sarcoidosis.Rate this question:
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- 7.
A 33 year old female presents to her physician complaining that she is not able to feel touch sensation along her chin just below her lower lip. MRI reveals a small basal tumor compressing structures that are exiting what landmark?
- A.
Foramen Rotundum
- B.
Foramen Ovale
- C.
Foramen Spinosum
- D.
Jugular Foramen
Correct Answer
B. Foramen OvaleExplanation
Cranial nerve V (Trigeminal N.) provides sensation to the face. More specifically, the third branch of the trigeminal nerve (V3) provides sensation to the lower-most portion of the face below the lower lip. It exits the neurocranium at the foramen ovale.Rate this question:
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- 8.
A 25-year-old man riding his motorcycle at 20 mph suddenly hits a pothole in the road and was ejected through the air landing headfirst on the left, lateral side of his skull. The man was taken to the emergency department and subsequent radiographic studies were undertaken that revealed damage to structure at the arrow (see below). Which of the following clinical manifestations will most likely be observed in this patient?
- A.
Loss of taste and general sensation to the anterior 2/3 of the tongue
- B.
Obstructive hydrocephalus
- C.
Non-obstructive hydrocephalus
- D.
Epidural hematoma
- E.
Trigeminal neuralgia
Correct Answer
D. Epidural hematomaExplanation
Blunt trauma to the lateral aspect of the skull will most likely fracture the pterion because this is the weakest part of the skull; damage to the pterion will subsequently damage the middle meningeal artery leading to an epidural hematoma.Rate this question:
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- 9.
Which of the following provides the surface atop which rests the basilar artery?
- A.
Lesser wing of sphenoid
- B.
Optic canal
- C.
Cribiform plate
- D.
Clivus
- E.
Anterior clinoid process
Correct Answer
D. ClivusExplanation
The lesser wing of the sphenoid provides the posterior border of the anterior cranial fossa. The optic canal is the path of exit for CN II and the ophthalmic artery. The cribiform plate contains foramina through which neurons of CN I pass. The anterior clinoid processes are bilateral structures anterior to the hypophysial fossa.Rate this question:
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- 10.
A 25-year-old man is brought into the emergency room following a motorcycle-versus-tree MVA with confusion, unilateral pupillary dilation, and altered level of consciousness. A CT of the head reveals a hematoma crossing the midline. The artery most likely to have been ruptured is a branch of which of the following?
- A.
Posterior auricular artery
- B.
Maxillary artery
- C.
Lateral nasal artery
- D.
Transverse facial artery
- E.
Angular artery
Correct Answer
B. Maxillary arteryExplanation
The artery in question is the middle meningeal artery, a branch of the (if you want to be more specific here, it is a branch from the first part of the the maxillary artery)maxillary artery (which is a branch of the external carotid artery). The hematoma is an epidural hematoma, which is slightly more likely to occur in younger patients. Choices A and D are also both branches of the external carotid artery, but not the ones in question here. Choices C and E are terminal branches of the facial artery.Rate this question:
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- 11.
Face and Scalp Sensation to the lower lip is supplied what branch of which cranial nerve?
- A.
Cervical branch of CN VII
- B.
Marginal mandibular branch of CN VII
- C.
Marginal mandibular branch of CN V
- D.
Maxillary branch of CN V
- E.
Buccal branch of CN VII
Correct Answer
C. Marginal mandibular branch of CN VExplanation
CN V3 supplies sensation to the lower face including the lower lip. CN VII supplies motor innervation to the muscles of facial expression.Rate this question:
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- 12.
A middle-aged patient arrives at your office complaining of loss of sensation over the face. You examine different regions of the face. During your inspection, you examine the skin over the angle of the mandible and notice a lack of sensation in this area. Which nerve supplies this region?
- A.
V1 of the Trigeminal nerve
- B.
V2 of the Trigeminal nerve
- C.
V3 of the Trigeminal nerve
- D.
Marginal mandibular
- E.
Posterior rami of C2-C3
- F.
Greater auricular nerve
- G.
Lesser occipital nerve
Correct Answer
F. Greater auricular nerveExplanation
The greater auricular nerve supplies the angle of the mandible in addition to the superioanterolateral neck. Answers A-C cover the face with the exception of the angle of mandible. The marginal mandibular nerve is a branch of the facial and supplies motor to the face, not sensation. The posterior rami of C2-C3 is not correct. If it had said anterior rami, then it would have been correct, since the greater auricular consists of C2-C3. The lesser occipital nerve is found more posterior to our region of interest.Rate this question:
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- 13.
A 43 year old man presents with Bell's Palsy. Which one of the following is LEAST likely damaged?
- A.
Zygomaticus Minor
- B.
Orbicularis Oris
- C.
Risorius
- D.
Masseter
- E.
Orbicularis Oculi
Correct Answer
D. MasseterExplanation
The Masseter is innervated by the Trigeminal nerve (V3) along with the Temporalis, Medial & Lateral pterygoids. These muscles comprise the ‘muscles of mastication’Rate this question:
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- 14.
If CN VII were ligated bilaterally which muscle on the face would still function properly?
- A.
Risorius
- B.
Masseter
- C.
Buccinator
- D.
Zygomaticus Minor
Correct Answer
B. MasseterExplanation
All of the muscles listed are innervated by the Facial nerve except for the Masseter muscle which is innervated by CN V3 .Rate this question:
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- 15.
Following surgery to remove a parotid tumor, a 45 year old female presents to her physician stating that whenever she sits down at the dinner table to ear, she begins to sweat profusely. What is the most likely explanation for her development of Frey Syndrome?
- A.
Regrowth of severed presynaptic parasympathetic fibers from CN IX to sweat glands
- B.
Regrowth of severed postsynaptic parasympathetic fibers from CN IX to sweat glands
- C.
Regrowth of severed presynaptic sympathetic fibers from CN V1 to sweat glands
- D.
Regrowth of severed postsynaptic parasympathetic fibers from CN V3 to sweat glands
Correct Answer
D. Regrowth of severed postsynaptic parasympathetic fibers from CN V3 to sweat glandsExplanation
Following surgery around the parotid gland, one possible complication is Frey Syndrome, a condition in which sweating occurs instead of salivating as a response to eating. One possible explanation is the regrowth of severed postsynaptic parasympathetic fibers during surgery to innervate sweat glands instead of salivary glands. Although the main salivary gland, the parotid gland, is innervated by CN IX, the postsynaptic parasympathetic fibers are carried by the auriculotemporal nerve, a branch of V3.Rate this question:
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- 16.
A 30-year-old female is giving birth vaginally, the obstetrician uses forceps to pull the baby’s head out by the mastoid processes. What is most at risk and possible result?
- A.
Vestibular n. and Battle signs
- B.
Glossopharyngeal n. and Ear sensory loss
- C.
Internal carotid n. and Horner’s syndrome
- D.
Facial n. and Bell’s palsy
- E.
Ophthalmic n. and maxillary sensory loss
Correct Answer
D. Facial n. and Bell’s palsyExplanation
The facial nerve will come out between the styloid and mastoid process, Any significant trauma to that area will damage the facial nerveRate this question:
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