The orbit, eye and ear Flashcards
what muscle does the trochlear nerve supply?
superior oblique
which number cranial nerve is the trochlear nerve?
CN IV
list the muscles involved in eye movement
lateral rectus, superior rectus, inferior rectus, medial rectus, superior oblique inferior oblique muscles
which nerve supplies the lateral rectus muscle?
CN VI - abducens nerve
which cranial nerve has three divisions (name and number)?
CN V - trigeminal nerve
what are the divisions of the trigeminal nerve?
- opthalmic nerve
- maxillary nerve
- mandibular nerve
what is CN II called?
optic nerve
which muscles does the oculomotor nerve (CN III) supply?
medial rectus
superior rectus
inferior rectus
inferior oblique
nasociliary branch is part of which Cranial nerve?
it is part of the ophthalmic division of the 5th Cranial nerve (CN V)
what nerve supplies the lateral rectus muscle?
abducent nerve (it is a motor nerve)
what do lesions to the sympathetic fibres cause?
pupil to not dilate, remaining small and constricted
What does compression to the parasympathtic neurones in the oculomotor nerve do?
pupil remains dilated!
compression ca occur due to swelling and oedema of the brain due to increased intracranial pressure.
what is the blood supply to the eye and orbit?
ophthalmic artery
what are the branches of the ophthalmic artery?
- anterior and posterior Ethmoidal arteries - supply the ethmoid air sinuses (medially)
- central artery of the retina - travels in the nerve to the retina.
contraction of the medial rectus muscles does what?
adducts the eye
contraction of the lateral rectus muscle does what?
abducts the eye
If you look to your left, which muscles are contracting?
in the left eye - lateral rectus is contracting
in the right eye - medial rectus muscle is contracting
when in the orbital axis (abduct) what do the superior and inferior recti muscle do?
these muscles only elevate and depress the abducted eye