Block 5 Anat Skul Cranial Fossa Face Scalp Ta's W Expl

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

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.

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.

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.

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

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.

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.

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.

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

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.

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

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

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.

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.

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.

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.