Cranial Nerves Part 1 Flashcards
What is the only sensory system that does not go through the thalamus to get to the cerebral cortex?
Olfactory system
The right brain sees the ______ visual field
Left
The left brain sees the ______ visual field
Right
Unilateral anopsia is observed in your pt. Where on the optic n. tract is the lesion?
anterior to the optic chiasm
Left visual field homonymous hemianopsia is noted. Where is the lesion?
Behind the optic chiasm on the right side of the optic n. tract
Bitemporal hemianopsia is observed d/t an enlarged pituitary gland. Where is the lesion/pressure?
On the optic chiasm
*only the medial vision is working because the temporal fibers don’t cross the optic chiasm and they see the medial visual fields
Which CNs are responsible for extra-ocular conjugate movement?
CN III (oculomotor n.)
CN IV (trochlear n.)
CN VI (abducens n.)
Where does CN III arise from?
Interpeduncular fossa (also emerges around the posterior cerebral arteries)
What muscle of the eye allows it to focus on an object?
Ciliary m.
When focusing on a distance object, the ciliary m. _______ and the lens gets ______
relaxes
thinner
When focusing on a close object, the ciliary m. _______ and the lens gets _______
contracts
thicker
What CN does most of the work w/ the eye?
CN III (oculomotor n.)
What CN rotates eye diagonally down and out?
CN IV (trochlear n.)
What is the fx of CN IV?
rotates the eye diagonally down and out
What CN innervates the Superior oblique m.?
CN IV (trochlear n.)
What CN innervates the lateral rectus?
CN VI (abducens n.)
What CN (including the specific branch) innervates the medial rectus m.?
Inferior branch of CN III (oculomotor n.)
What CN rotates the eye out?
CN VI (abducens n.)
Pt. has strabismus and their extraocular muscles are anatomically normal. What nerve is the lesion on?
CN VI (abducens n.)
CN that emerges from the ventrolateral pons
CN V (Trigeminal n.)
CN that arises in the pontomedullary grove
CN VI (abducens n.)
The only CN that emerges dorsally
CN IV (trochlear n.)
The only CN that is crossed
CN IV (trochlear n.)
Name the 3 divisions of CN V
V1 - opthalamic n.
V2 - maxillary n.
V3 - mandibular n.
Supplies gen. sensation from anterior nose to upper face and forehead
V1 (opthalamic n.) branch of CN V
Supplies gen. sensation from upper lip to lower eyelid and back to nasopharyx
V2 (maxillary n.) branch of CN V
Supplies gen. sensation from lower lip back to TMJ and posterior temple
V3 (mandibular n.) branch of CN V
What CN causes pupil constriction?
CN III (oculomotor n.)
Parasympathetic stimulation = pupils are ________
constricted
What type of herniation affects CN III?
Uncal herniation
What br. of CN V leaves the skull via the foramen ovale?
V3 (mandibular n.)
What br. of CN V leaves the skull via the foramen rotundum?
V2 (maxillary n.)
What br. of CN V leaves the skull via the superior orbital fissure?
V1 (Opthalamic n.)
What CN branch innervates the pterygoid muscles, massetter muscles, temporalis muscles?
V3 Mandibular branch of CN V
What space does the medial & lateral pterygoid muscles reside?
Infratemporal fossa
