The eye and its muscles Flashcards
what part of the globe of the eye do all the extraocular muscles attach to
the sclera
3 actions of the inferior oblique muscle
elevates
abducts
laterally rotates
3 actions of the superior oblique muscle
depresses
abducts
medially rotates
where does the superior oblique muscle originate
the roof of the sphenoid bone
what is the purpose of the 2 oblique muscles
to counteract rotation created by the recti as the recti dont produce a pure action, since their long axis is not in line with the
what is the main abductor of the eye
lateral rectus, but the obliques help this action
3 actions of the superior oblique muscle
elevates, medially rotates, adduction
what nerve innervates levator palpibrae superioris
oculomotor nerve CN 3
what muscle within the upper eyelid has innervation via the sympathetic system to open the eye lid
superior tarsal muscke
where does the the superior tarsal plate of the upper eyelid originate
the lesser wing of the sphenoid bone
what does the levator palpabrae superioris insert onto
the superior tarsal place
what gland is on a more lateral plane than the latral rectus muscle
the lacrimal gland
what is the conscious innervation of the lacrimal gland
trigeminal nerve, V1
what 2 eye muscles have isolated actions and so are tested first
medial and lateral rectus
what innervates the medial rectus muscle
oculomotor nerve
what position do we put the eye in to test inf and sup oblique
put the eye in a position, using superior and inferior rectus that would give maximum rotation and look for complete correction by the obliques
to test superior obique, what position would you put the eye into
abduct the eye 30 degrees, and look up, so that inferior rectus would be giving maximum lateral rotation
to test inferior oblique, what position would you put the eye in
look medially 30 degrees, then look down. so that superior rectus would be trying to give maximum medial rotation
does inferior oblique stop intorsion or extortion?
intorsion
why do you ask the patient to look 30 degrees laterally to test superior rectus
the pull of the muscles to be parallel to the optic axis
eye problems: what is a duction
this is abduction or adduction of just one eye, so monocular
eye problems: what are versions
bilateral, this is adduction or abduction of both eyes, this is dextroversion as they cannot straighten their eyes
eye problems: what are vergences
this is binocular, but where the eyes aren’t pointing in the same direction, so disconjugate, so both are looking medially
when going down stairs and seeing 2 sets, which muscle should be working. which one is not working and what type of movement is it failing to oppose
inferior rectus and superior oblique.
superior oblique, lateral rotation (extorsion)
when seeing 2 images when going up stairs, what action is unopposed by an oblique muscle
medial rotation (intorsion). as inferior oblique isn’t working
what type of function is lost in the head as a result of horner’s syndrome
sympathetic function
what muscle of the eyelid is affected by horner’s syndrome
superior tarsal muscle as this has sympathetic innervation
what type of autonomic innervation is sent via the oculomotor nerve to the levator palpabrae superioris
parasympathetic
when would you surgically induce horner’s syndrome
when a patient suffers hyperhydrosis and it is affecting their life adversely
what ganglion is obliterated to treat hyperhydrosis
cervicothoracic ganglion
name 4 problems associated with a tumour in the jugular foramen
dysphonia, dysphagia, loss of taste and sensation to the posterior third of the tongue, unilateral wasting of the trapezius and sternocleidomastoid
foramen magnum syndrome is:
compression of the lower brain stem, the spinal cord or part of the cerebellum
give 3 results of foramen magnum syndrome
pain in the head, neck, limbs and trunk, vertigo (cerebellum) and gait disturbance, pyramidal signs.
what part of the sympathetic roots (of t1 to L2) supply the orbit? and what ganglion do they have to pass through to get there?
T1. the stellate ganglion.
what 2 structures in the orbit have sympathetic innervation
the dilator pupilae muscle and the blood vessels
what 2 CNs supply parasympathetic innervation to the orbit, what nucleus do they pass through first in the brainstem.
oculomotor, edinger-westphal nucleus.
facial, goes to a ganglion in the teporal bone first though, not the edinger-westphal in the brainstem.
drainage of the tears from the lacrimal gland to the nasal cavity.
lacrimal gland, globe, superior and inferior punctum, lacrimal canaliculi, lacrimal sac, nasolacrimal duct,inferior meatus of the nose.
what 3 structures are in the optic canal behind the eye
the opthalmic artery (which gives rise to the central retinal artery), optic nerve, superior opthalmic vein.
what ganglion is at the back of the orbit
the ciliary ganglion