The ocular motor nuclei and nerves Flashcards
What is the ocular motor system compromised of?
> EOM - 6 per eye
3 pairs of cranial nerves ( 3, 4, 6)
3 paired ocular motor nuclei in the brainstem
Numerous higher brain centres
What divisions are there in the higher hierarchical system?
Infra nuclear
Nuclear
inter nuclear
supra nuclear
What is inside the infra nuclear?
The EOM
What is inside the Nuclear?
Ocular motor neurones
What is inside the inter nuclear?
axons pathway
What is in the supra nuclear?
Brainstem nuclei generators
Control by higher centres
What does the 3rd nerve innervate and where is the third nerve ?
Oculormotor nerve from upper midbrain innervated the MR, SR, IR, IO
What does the 4th nerve innervate and where is the fourth nerve?
Trochlear nerve from the lower midbrain innervates the SO
What does the 6th nerve innervate and where is the sixth nerve ?
Abducences nerve from the mid caudal pons enervates the LR
What three axons take which course and where ?
The short intra cerebral course before exiting the brainstem
The long intra cranial course to reach the superior orbital fissure
The long intra orbital course to reach and innervate the target muscles
What do all nerves pass and go through?
All nerves pass along some arteries and some bones but all 3 nerves go through the superior orbital fissure and through the cavernous sinus
Where is the ocular motor nuclei located?
Ocular motor nuclei located at the midline in upper midbrain at the level of superior colliculus
What does the ocular motor nuclear complex contain?
4 somatic motor neurone pools
1 midline somatic motor neurone pools
2 autonomic motor neurone pools
What is the function of 4 somatic motor neurone pools?
Innervate the oculorotatory muscles (MR SR IR IO)
What is the function of 1 midline somatic motor neurone pools?
Innervates the LPS
What is the function of 2 autonomic motor neurone pools?
innervate different neurones in ciliary ganglion, which supply the sphincter pupillae and ciliary muscles
What is the name of 1 midline somatic motor neurone pool?
Caudal central nucleus