Skull And Cranial Fossa - Face And Scalp

1. 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?

Facial Nerve

Ophthalmic Division of Trigeminal Nerve

Mandibular Division of Trigeminal Nerve

Ophthalmic Artery

Facial Artery

The Optic nerve (CN II) and the Ophthalmic artery both travel through the optic canal.

Explanation

The Optic nerve (CN II) and the Ophthalmic artery both travel through the optic canal.

2. 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?

Foramen Rotundum

Foramen Ovale

Foramen Spinosum

Jugular Foramen

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.

Explanation

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.

3. ________ exits the skull through the internal acoustic meatus ; however, only _______ exits the skull through the stylomastoid foramen .

Facial nerve only , Facial nerve only

Vestibulocochlear nerve only , vestibulocochlear nerve only

Both facial and vestibulocochlear nerves , Both facial and vestibulocochlear nerves

Both facial and vestibulocochlear nerves, Only facial nerve

Both facial and vestibulocochlear nerves , Only vestubulocochlear nerve

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.

Explanation

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.

4. 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?

Occipital sinus

Sigmoid sinus

Straight sinus

Cavernous sinus

Superior petrosal sinus

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.

Explanation

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.

5. If CN VII were ligated bilaterally which muscle on the face would still function properly?

Risorius

Masseter

Buccinator

Zygomaticus Minor

All of the muscles listed are innervated by the Facial nerve except for the Masseter muscle which is innervated by CN V3 .

Explanation

All of the muscles listed are innervated by the Facial nerve except for the Masseter muscle which is innervated by CN V3 .

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?

Foramen rotundum

Foramen ovale

Jugular foramen

External acoustic foramen

Stylomastoid foramen

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.

Explanation

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.

7. What structures pass through the superior orbital fissure?

Cranial nerves III, IV, VI , VI, and Middle Meningeal artery

Cranial nerves III, IV, VI , VI, and Ophthalmic artery

Cranial nerves III, IV, VI,2,3 , VI

Cranial nerves III, IV, VI , VI, and Ophthalmic vein

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.

Explanation

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.

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?

Loss of taste and general sensation to the anterior 2/3 of the tongue

Obstructive hydrocephalus

Non-obstructive hydrocephalus

Epidural hematoma

Trigeminal neuralgia

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.

Explanation

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.

9. Face and Scalp Sensation to the lower lip is supplied what branch of which cranial nerve?

Cervical branch of CN VII‬‬‬‬‬‬‬‬‬‬‬‬

Marginal mandibular branch of CN VII

Marginal mandibular branch of CN V‬‬‬‬‬‬‬‬‬‬‬‬

Maxillary branch of CN V‬‬‬‬‬‬‬‬‬‬‬‬

Buccal branch of CN VII

CN V3 supplies sensation to the lower face including the lower lip. CN VII supplies motor innervation to the muscles of facial expression.

Explanation

CN V3 supplies sensation to the lower face including the lower lip. CN VII supplies motor innervation to the muscles of facial expression.

10. 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?

Superior ophthalmic vein

Inferior ophthalmic vein

Cavernous sinus

Ophthalmic artery

CN I

CN V: V2 Branch

Ophthalmic nerve

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.

Explanation

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.

11. Which of the following provides the surface atop which rests the basilar artery?

Lesser wing of sphenoid

Optic canal

Cribiform plate

Clivus

Anterior clinoid process

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.

Explanation

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.

12. A 43 year old man presents with Bell's Palsy. Which one of the following is LEAST likely damaged?

Zygomaticus Minor

Orbicularis Oris

Risorius

Masseter

Orbicularis Oculi

The Masseter is innervated by the Trigeminal nerve (V3) along with the Temporalis, Medial & Lateral pterygoids. These muscles comprise the ‘muscles of mastication’

Explanation

The Masseter is innervated by the Trigeminal nerve (V3) along with the Temporalis, Medial & Lateral pterygoids. These muscles comprise the ‘muscles of mastication’

13. 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?

Vestibular n. and Battle signs

Glossopharyngeal n. and Ear sensory loss

Internal carotid n. and Horner’s syndrome

Facial n. and Bell’s palsy

Ophthalmic n. and maxillary sensory loss

The facial nerve will come out between the styloid and mastoid process, Any significant trauma to that area will damage the facial nerve

Explanation

The facial nerve will come out between the styloid and mastoid process, Any significant trauma to that area will damage the facial nerve

14. 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?

Posterior auricular artery

Maxillary artery

Lateral nasal artery

Transverse facial artery

Angular artery

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.

Explanation

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.

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?

Regrowth of severed presynaptic parasympathetic fibers from CN IX to sweat glands

Regrowth of severed postsynaptic parasympathetic fibers from CN IX to sweat glands

Regrowth of severed presynaptic sympathetic fibers from CN V1 to sweat glands

Regrowth of severed postsynaptic parasympathetic fibers from CN V3 to sweat glands

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.

Explanation

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.

16. 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?

V1 of the Trigeminal nerve

V2 of the Trigeminal nerve

V3 of the Trigeminal nerve

Marginal mandibular

Posterior rami of C2-C3

Greater auricular nerve

Lesser occipital nerve

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.

Explanation

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.