Eye - muscles Flashcards
Trochlea nerve supplies the SO
What are the 3 nerves of the extrinsic ocular nerves?
3 4 6
What is the pneumonic for muscles and cranial nerves?
SO 4
LR 6
everything else 3
What innervation is the 3rd cranial nerve?
Occulomotor
What CN carry parasympathetic?
3 7 9 10
What nerve innervates glands?
CN 7
Makes things secrete
What type innervation is the 4th cranial nerve?
Autonomic
What is the role of the optic nerve?
Carries visual impulses from the eyeball. Leaves orbit through the optic foramen
What way does the mesial recuts muscle help you move the eye?
Medially
Towards nose
What way does the lateral rectus allow the ye to move?
Laterally
Away from nose
Abduction
What muscle allow the eye to elevate?
Superior rectus
What muscle allows the eye to look down? (Depression)
Inferior rectus
What is the action of the superior oblique?
Intorsion
What does the inferior oblique muscle allow?
Extortion
When the superior oblique causes intosion, what is a consequence of this?
Depression and abduction
What other movement does the inferior oblique muscle cause?
Elevation
What does the abducens nerve innervate?
Lateral rectus
What does the trochlear nerve innervate?
Superior oblique
What muscles does the oculomotor nerve innervate?
Superior oblique and lateral rectus
What are the signs of CNIII n palsy?
Ptosis, and eye is down and out, pupil may be non reactive
What are the signs of CNIV palsy?
Eye shoots up when looking towards the nose
What is the sign of CNVI palsy?
Eye cannot abduct
Why would the reasons for CNIII palsy?
Diabetes - palsy and pupil find
Aneurism in brain - palsy and pupil involved
What is the normal pupil reaction to light?
Constriction
What is the significance of a third cranial nerve palsy and pupil involvement?
Aponeurosis
What is the fovea?
a small depression at the center of the retina. It provides the sharpest vision in the human eye
A = superior oblique
B = medial rectus
C = inferior oblique
D = inferior rectus
E = lateral rectus
F = superior rectus
What do the intrinsic eye muscles control?
Control pupil diameter
What is the visual pathway?
Optic nerve
Optic chiasm
Optic tract
To the thalamus and synapses
Optic radiation
What fibres cross over at the chiasm?
Nasal
What are the 2 categories of ocular muscles?
Intrinsic and extrinsic
What is the role of the intrinsic muscles of the eye?
Control pupil diameter and helps alter lens curvature to enable us to see near objects
What is the role of the extrinsic muscles of the eye?
Also called extraoccular muscles
Move the eye
What muscle is responsible for constricting the pupil?
constrictor pupillae by parasympathetic (CNIII)
What muscle allows the pupil to dilate?
Dilator pupillae by sympathetic (plexus around blood vessels)
What happens to the eye when you want to focus on near object?
Ciliaris muscles for focussing on near objects
When it constricts …
It makes the lense more convex, needed for focus
What happens to the pupil under parasympathetic innervation?
Constriction pupillae and Ciliaris muscle
What are the only muscles to have an origin at the anterior and posterior aspect of the orbit?
Oblique muscle
Inferior and superior oblique
What is the origin of the recti muscles?
Apex of the orbit from the annular fibrous ring
A = superior re the muscle
B = levator palpebrae superioris
What is a musc,e which is a,so classed as an extrinsic muscle of the eye?
LPS
Levator palpebrae superioris
What 2 extrinsic muscles does the oculomotor not supply?
SO
LR
Where does the oculomotor nerve synapse and what innervation does it carry?
at the ciliary ganglion
parasympathetic
What does the optic nerve innervate?
Carries visual impulses from eyeball. Leaves orbit through foramen
