Cranial nerves 5 Flashcards
What bones form the margin and walls of the orbit
- Frontal (roof)
- Maxilla (floor)
- Zygoma (lateral wall)
- Lacrimal (medial wall)
What is the axis of orbit
45 degrees
this is important is muscle action
medial wall extends farther anteriorly than the lateral wall
what is the origin of the 4 rectus muscles
tendinous ring
what type of fat fills the orbit and supports the eyeball
retrobulbar
what is amaurosis fugax
central artery of the retina (which runs through the optic nerve) may be occluded by a thrombus
blindness
where does the meninges extend to in the eye
the sclera
what sign of raised intracranial pressure can be seen in the eye
papilloedema
due to slowed retinal venous drainage via the central retinal vein
where is the lacrimal gland found
upper, lateral corner of the orbit
tears are secreted into the conjunctival sac and washed across the eye
what can malfunction of obicularis oculi lead to
sagging of the lower lid, leakage of tears and dry eyes
corneal ulceration
describe the drainage of tears
punctae to canaliculi to lacrimal sac to nasolacrimal duct to inferior meatus (nasal cavity)
what is the function of tarsal glands
lubricate the eyelids
may form a cyst
where can stys form
ciliary (sebaceous glands) next to the hair follicles
what is the nerve supply to LPS
striated and smooth muscle fibres from occulomotor and carotid plexus in cavernous sinus
what is the parasympathetic supply to the lacrimal glands
superior salivatory nucleus sends primary fibres in nervus intermedius to the facial nerve.
they travel to the greater petrosal nerve then nerve of pterygoid canal
they synapse in the pterygopalatine ganglion and hitch hike to the lacrimal gland on the zygomatic branch of V2
Which muscles attach behind the axis of movement
obliques
this means that the pull the eyeball in the opposite direction suggested by their names
they both act to draw the eyes laterally
