Skull, Scalp, and Face Flashcards
Name the bones of the skull (PESTOF)
Parietal - 2 Ethmoid - 1 Sphenoid - 1 Temporal -2 Occipital - 1 Frontal - 1
Describe the layers of the scalp
Skin
Closed connective tissue (fat, blood vessels, and nerves)
Aponeurosis ( flattened tendonof the occipitofrontalis)
Loose ct (separates scalp proper from pericranium)
Pericranium (periosteum of the calvarium, attached by sharpeys fibers)
Innervation: CN V, C2 and C3
Blood supply external carotid artery
Where are the muscles of facial expression derived from and what is there innervation
Mesoderm of the 2nd branchial arch
innervated by branches of CN VII: Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical
Describe levator palpebrae superioris
Not a muscle of facial expression and is supplied by CN III
Smooth muscle component = tarsal - innervated by sympathetic fibers which arise from stellate ganglion
Frontalis muscles role in lesions
Allows differentiation of UML and LML
In UML - caused by stroke, patient is able to wrinkle forehead on the affected side because of bilateral innervation
In LML - Bell’s palsy, patient will not be able to wrinkle forehead on affected side, muscles on affected side will be paralyzed (orbicularis oculi, rizorius, buccinator and orbicularis oris)
Describe the eye
3 layers: Sclera (anterior part called cornea), choroid (blood vessels), and retina (photosensitive)
What separates the aqueous from the vitreous humor of the eye
biconvex lens
What separates the anterior and posterior chambers of the eye containing the aqueous humor
pigmented iris
What secretes the aqueous humor
ciliary body that is attached to the lens
What causes glaucoma
Blockage of the scleral venous sinus (canal of Sclemm) preventing drainage of aqueous humor
Describe the macula lutea
Oval yellow spot in the retinal layer
It’s center is called the fovea centralis in which the highest concentration of of cones
(Optic disc has no receptors)
Describe the role of the ciliary body
Produces aqueous humor
Parasympathetic stimulation of the ciliary body causes contraction relaxing the suspensory ligament causing the lens to thicken and to focus on near objects
Relaxation of the ciliary muscle results in increased tension in the suspensory ligament of the lens causing the lens to flatten allowing for focus of objects far off
Describe the different areas of the ear
External - consists of the pinna and external ear canal
Middle - contains malleus, incus, and stapes responsible for amplification of sound
Internal - cochlea (hearing) and semicircular canals along with the utricle and saccule (balance)
Describe the cochleas function
Coiled tube filled with perilymph surrounding the scala media which is filled with endolymph
Vibration in the outer tube (scala vestibuli and tympani) vibrates the basilar membrane on which the organ of corti is located
Describe the organ of corti’s function
Has outer hair cells embedded in the tectorial membrane which are responsible for converting mechanical vibrations into electrical impulses
