17 - Eye Movements Flashcards
What are the different extrinsic and intrinsic muscles of the eye?
- Muscles of the eyelid: LPS and OO
- Extra ocular muscles that move eyeball
- Muscles of iris to control pupil
- Muscles of ciliary body to control lens thickness
Label the following extra-ocular muscles of the eye.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/264/q_image_thumb.png?1574331133)
All attach to sclera of the eye and recti come from common tendinous origin around optic canal
LPS on top of superior rectus
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/264/a_image_thumb.png?1574331282)
Why do we need binocular vision?
- Allows us to have depth perception. Two images get sent to visual cortex and fused to be seen as one
- Can get depth diplopia if visual axes malaligned
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/268/a_image_thumb.jpeg?1574331448)
What is the nerve innervation to the extra occular muscles?
LR6SO4R3
What muscles are allowing this movement of the eyes?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/270/q_image_thumb.png?1574331681)
Lateral (6) and medial (3) rectus
What action does superior rectus have on the eye if at primary resting gaze?
- SR inserts into superior anterolateral eye
- Elevates
- Adducts
- Slightly intorts
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/273/a_image_thumb.png?1574331886)
What action does inferior rectus have from primary resting gaze?
- IR inserts on anteroinferior surface of eye
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/275/a_image_thumb.png?1574332118)
- Depress
- Adducts
- Extorts
What action does superior oblique have?
- Functional pull from trochlea
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/279/a_image_thumb.png?1574332229)
- Intort
- Depress
- Abduct
What action does inferior oblique have?
- Extort
- Elevate
- Abduct
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/281/a_image_thumb.jpeg?1574332323)
What is the nerve palsy here?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/282/q_image_thumb.jpeg?1574332367)
- Issue with abduction as adduction so lateral rectus
- CN 6
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/282/a_image_thumb.png?1574332519)
What is the nerve palsy here?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/287/q_image_thumb.png?1574332610)
- Right eye held elevated, adducted and externally torted as head tilt so superior oblique lost
- CN 4 issue
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/287/a_image_thumb.png?1574332553)
How would you test the extra-occular muscles of the eye?
- Move eye medially or laterally before elevating and depressing
- H
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/291/a_image_thumb.jpeg?1574332758)
What can cause a cranial nerve palsy?
- Raised ICP e.g tumour or haemorraghe
- Vascular diease like hypertension or diabetes
How would an occulomotor cranial nerve palsy present?
- Pupil spared if vascular but if compressive dilated pupil
- Ptosis
- Down and out
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/294/a_image_thumb.png?1574333416)
How would a trochlear cranial nerve palsy present?
- Loss of SO so elevation, extorted and adducted with head tilt to compensate
- Worsening diplopia when looking down and medially e.g down stairs or book
![](https://s3.amazonaws.com/brainscape-prod/system/cm/435/540/295/a_image_thumb.jpeg?1574333672)