Efferent Pathway

Brainstem is located

in between the forebrain and spinal cord

What is included in the brainstem?

midbrain, pons, medulla

In the LGN what is the tectum?

the roof

What are the three branches of the LGN (visual info processing)?

magnocellular- peripheral

parvocellular - central vision

konocellular - color

What does the superior colliculus do?

coordinates eye movement

What does the inferior colliculus do?

auditory function

The oculomotor is cranial nerve III (3), what are the nuclei?

‘Oh! Some Lovely Eyes’

oculomotor nuclei

superior rectus nuclei

levator (central caudal nucleus)

Edinger Westphal Nuclei (accessory 3rd nerve)

What is Oh, in ‘Oh! Some Lovely Eyes?

The oculomotor nuclei which is from the midbrain and is IPSILATERAL

What is Some? in Oh, Some Lovely Eyes?

Superior Rectus Nuclei

• it decussates (CROSSES OVER) so it supplies contralateral Superior Rectus

What is Lovely in Oh, Some Lovely Eyes?

The Levator nuclei aka central caudal nucleus,

• one CENTRAL nucleus in the midline that supplies both levators

What does Eye, stand for?

• edinger westphal aka _________

accessory 3rd nerve

• parasympathetic for the iris sphincter and ciliary muscles

• sympathetic for tarsal muscles of the eyelids

Where do fibers from each of the oculomotor (3) nucleus’ pass through?

(hint: sophies favorite nucleus)

Red Nucleus

What kind of effect do “Oh, Some Lovely Eyes’ have?

ipsilateral effect (all on same side)

• down and out position of the eye

• ptosis of the eye

• mydriasis of the eye

What is the saying SO4 ……

LR 6, ATR 3

Trochlear is CN 4 IV. Where does it originate and what does it do?

originates in the midbrain, enters superior orbital fissues above the muscle cone and

~SO~ decussates (crosses over) so it is contralateral (why we test the EOMS the way we do?)

What is crazy to take away about the Abducens CN6?

It is the most likely to be damaged as it is the longest pathway to get to the orbit making it more susceptible to injury.

meanwhile lil sensitivity (abducens) can’t handle any supression.

What does the abducens innervate?

The abducens innervates the LR and travels through the MLF (medial longitudinal fasciculus)

the MLF (medial longitudinal fasciculus) connects VOAT which links what?

eye movement and the vestibular system

Vestibulocochlear

Oculomotor

Abducens

Trochlear

Tell me about the facial like your life depends on it?

Its CN VII (7),

the longer branch does motor functions

the smaller branch does sensory and sends parasympathetic to. the lacrimal gland

THE FIVE BRANCHES ARE

TO ZANZIBAR BY MOTOR CAR

What are the five branches of the facial nerve?

"To Zanzibar By Motor Car"

• T = Temporal (muscles of the forehead)

• Z = Zygomatic (muscles around the eyes)

• B = Buccal (muscles of the cheek)

• M = Marginal mandibular (muscles of the lower lip)

• C = Cervical (muscles of the neck)

If CN VII gets swelling, what happens?

Bell’s palsy

• you can’t close your eye

• CN 3 (oculomotor) holds the eye open and 7 (facial) closes it