Oculomotor Flashcards
What base of skull foramina does the oculomotor nerve pass through? In which cranial fossa is this?
Superior orbital fissure / middle cranial fossa
What information is carried on the oculomotor nerve?
Motor and parasympathetics
What are the functions of the oculomotor nerve?
Motor supply to the following muscles: medial rectus, inferior oblique, superior rectus, inferior rectus and levator palpebrae superioris AND pupillary constriction via sphincter pupillae muscle
The motor component of CNIII originates where? What is this responsible for?
Oculomotor nucleus in the midbrain (midline) - responsible for eye movements
The parasympathetic component of CNIII originates where? This can also be known as what?
Edinger-Westphal nucleus / accessory oculomotor nucleus
What type of nucleus is the Edinger-Westphal nucleus?
A parasympathetic pre-ganglionic nucleus
The Edinger-Westphal nucleus is important in causing what two things?
Pupillary constriction and accomodation reflex
The Edinger-Westphal nucleus causes pupillary constriction by doing what?
Activating the sphincter pupillae muscle
The Edinger-Westphal nucleus causes the accomodation reflex by doing what?
Activating ciliary muscles via the ciliary ganglion
Describe the intracranial path of the oculomotor nerve?
Connects with the CNS in the midbrain and then travels towards the orbit in the lateral walls of the cavernous sinus
After passing through the superior orbital fissure, what does CNIII do?
Passes into the orbit to supply most of the extraocular eye muscles, and the parasympathetic fibres synapse in the ciliary ganglion
How is the parasympathetic branch of CNIII tested?
Using a light to check for pupillary constriction
How is the motor branch of CNIII tested?
H test to assess the eye movements
