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CN VI name, exit location, sensory or motor, function
abducens; exits at junction of pons and medulla; motor; innervates lateral rectus mm of the eye (controls lateral movement)
Brainstem contains how many of the 12 cranial nerves?
10
medulla oblongata contains what structures?
pyramid, olive, inferior cerebellar peduncle
You have a patient who presents with decreased sensation to the anterior two thirds of their tongue. What cranial nerve is damaged?
CN VII; facial
CN II is damaged. What is the likely presentation upon examination? Sensory or motor?
Optic nerve; decreased visual acuity, color perception, peripheral visual perception. This patient has decreased ability of carrying visual information from the retina to the brain.
Sensory (afferent)
CN IX, CN X, CN XI, CN XII
error detection/control center
medullar olives (anterior)
controls heartbeat, rate of breathing, diameter of blood vessels, and helps coordinate swallowing, vomiting, hiccoughing, couching, sneezing
medulla oblongata
A patient presents with heart rate inconsistencies. What cranial nerve may cause this?
CN X (vagus)
You have a patient who presents with complaints of being unable to hear on one side. What cranial nerve could be involved and what are the tests to determine the type of hearing loss?
CN VIII (vestibulocochlear), Weber, Rhine
CN IX name; exit location; sensory or motor; function
What structure is signaled from the error detection center when movement deviates from the planned movement?
Cerebellum
Function - contains nerve reflex centers involved in auditory reflexes
Region - part of midbrain
You are seeing a patient who is unable to make facial expressions and chew on half of their face. What is the CN involvement?
Facial (CN VII), Trigeminal (CN V)
The lateral rectus muscle is damaged in your patient and they are unable to track their visual field laterally. What cranial nerve is damaged? Is it efferent or afferent?
Abducens (XI); efferent (motor)
What structure is the major decussation of descending fibers? What are these fibers called (name of tract)
anterior medullary pyramids; lateral corticospinal tracts
3 tests for CN II
Optic nerve; sensory only; 1. visual acuity (snellen chart); 2. color perception; 3: peripheral visual percection
CN XI controls what muscles? What is the test for these muscles?
spinal accessory- SCM (sternocleidomastoid) - neck rotation against resistance, trapezius - shoulder shrug against resistance
You are seeing a patient who has a lesion at the inferior cerebellar peduncle. Connection from the medulla to what structure may be impaired? What could be a possible symptom of this lesion?
Cerebellum; deviation from planned movements
A patient has damage to CNs III and IV. What structure of the brainstem could have been damaged to cause these deficits? What deficits might you see?
Midbrain; CN III - oculomotor - deficits with eye movements, pupil constriction, eyelid opening; CN IV - trochlear - deficits with rotational movements of the eye
Structures/function of midbrain
cerebral peduncle, superior colliculus, inferior colliculus, superior cerebellar peduncle, CN III (oculomotor), CN IV (trochlear)
function: aids in movement, visual and auditory processing
Structure/function of pons
Middle cerebellar peduncles - connects cerebellum to pons
CN V (trigeminal), CN VI (abducens), CN VII (facial), CN VIII (vestibulocochlear)
*assists in controlling autonomic functions, processes and relays info to/from cerebellum*
CN X - name, exit location, sensory or motor, function
Vagus; medulla; both; responsible for HR regulation, GI peristalsis (contraction/relaxation), sweating (diaphoresis), mm. movements in mouth, incl. speech and keeping larynx open for breathing
You are evaluating a patient who is having trouble swallowing and you suspect that they should be referred to a speech pathologist. What is the cranial nerve that may be damaged?
Hypoglossal (XII), X, IX
middle cerebellar peduncle, CN V, CN VI, CN VII, CN VIII; impairments with controlling autonomic functions (sleep, swallowing, respiration, bladder, hearing, equilibrium, taste, eye movements, facial expressions/sensation, posture)