Lecture 16 - High Yield Flashcards
What is the auricle?
Layer of skin over cartilage framework; lobule = fibrous fatty tissue with no cartilage
What provides sensory innervation for the outer ear?
Great auricular nerve, auriculotemporal nerve, and lesser occipital nerve
Describe the tympanic membrane
Dense fibrous membrane covered by skin externally and mucosa internally
What are the auditroy ossicles?
Malleus (attached to tympanic membrane), incus, stapes (attached to oval window, also called fenestra vestibuli)
Describe the stapedius muscle
Inserts onto neck of stapes and contracts reflexively in response to loud sounds; innervated by CN VII
What makes up the roof of the orbit?
Orbital plate of frontal bone, lesser wings of sphenoid; related to frontal cerebral lobes; special features include fossa for lacrimal gland
What makes up the floor of the orbit?
Orbital plate of maxilla, zygomatic, orbital process of palatine; related to maxillary sinus; special features include infraorbital groove and canal, which contain infraorbital nerve (continuation of CN V2) and artery (branch of external carotid)
What makes up the medial wall of the orbit?
Lacrimal, frontal, ethmoid; related to ethmoid air cells, sphenoid sinus, nasal cavity; special features include fossa for lacrimal sac and opening for nasolacrimal canal
What makes up the lateral wall of the orbit?
Zygomatic, greater wing of sphenoid, frontal; related to temporal fossa containing temporalis muscle and middle cranial fossa
What is the sympathetic and parasympathetic supply to the lacrimal apparatus?
Sympathetic: from T1 to superior cervical ganglion to lacrimal gland
Parasympathetic: from lacrimal nucleus via CN VII to sphenopalatine ganglion to lacrimal gland courtesy of CN V
What are the cranial nerves to the superior orbital fissure and what is the vein to this area?
III, IV, V-1 (ophthalamic branch; frontal, lacrimal, nasociliary), VI, superior ophthalamic vein
What are the cranial nerves to the optic canal and what artery is in this area?
II and ophthalamic artery
What are the cranial nerves to the inferior orbital fissure?
V2; infraorbital nerve, zygomatic branch, orbital branches
Where do the 6 extrinsic muscles of the eye originate from and what is their function?
Originate from a common annular tendon; control movement of the eyeball
What nerve innervates the inferior oblique, superior rectus, medial rectus, and inferior rectus muscles?
CN III
