Brain Stem + Cranial Nerves Flashcards
what are the 3 major subdivisions of the brainstem?
- medulla
- pons
- midbrain
what is a key concept about the caudal medulla?
- resembles rostral spinal cord
- same pathways for sensory + motor nuclei
CN 1
ofactory
CN 2
Optic
CN 3
Oculomotor
CN 4
Trochlear
CN 5
Trigeminal
CN 6
Abducens
CN 7
Facial
CN 8
Vestibulocochlear
CN 9
Glossopharyngeal
CN 10
Vagus
CN 11
Acessory
CN 12
Hypoglossal
which cranial nerves do we encounter in the medulla?
12, 11, 10, 9, 5
which cranial nerves do we encounter in the pons?
6, 7, 8
Trigeminal Nerve (5)
- motor
- sensory
- pain + temp (face)
- tactile - position sense (jaw)
what are the 3 divisions of the trigeminal nerve?
- ophthalmic
- maxillary
- mandibular
what type of sensory deficits are involved with the trigeminal nerve?
-loss of pain + temp on face
-loss of touch-pressure on face
-loss of position sense in jaw
(all ipsilateral)
what reflex is related to a deficit in the trigeminal nerve?
corneal reflex
what are the motor deficits in a damaged trigeminal nerve?
ipsilateral muscle paralysis in jaw
what kind of nerve is the hypoglossal nerve?
strictly motor nerve that supplies muscle and tongue
what is a result of lesions in the hypoglossal nerve?
ipsilateral paralysis atrophy of tongue
what are the two parts of the accessory nerve?
- cranial part (assist 9 and 10
2. spinal (muscles in neck)
what is clinical testing for the accessory nerve?
-spinal part + innervation of shoulder muscles
what are the 4 functional components of the vagus nerve?
- motor (pharynx + larynx)
- parasympathetic (thorax + abdomen)
- sensory (pharynx + larynx)
- taste (epiglottis in tongue)
what are the result of lesions in the vagus nerve?
-ipsilateral paralysis of pharyngeal + laryngeal muscles
what are signs of lesions in the vagus nerve?
- hoarseness
- difficulty swallowing
- difficulties in articulation
what are the 4 components of the glossopharyngeal nerve?
- motor (pharynx + larynx)
- parasympathetic (salivary gland)
- sensory (tonsil, pharynx, tongue)
- taste (tongue)
what reflex is often tested for the glossopharyngeal and vagus nerves? (9, 10)
gag reflex
what is a sign of medial medullary syndrome?
- contralateral loss of position sense
- ipsilateral paralysis of half of tongue
what is a cause for lateral medullary syndrome?
- occlusion of PICA
- occlusion of vertebral artery
what is a sign of lateral medullary syndrome?
- ipsilateral loss of pain + temp over face
- contralateral loss of pain + temp over body
- loss of gag reflux
what are the 2 components of the vestibulocochlear nerve?
- audition (cochlear)
- vestibular
what are the 3 central pathways from the vestibular nuclei?
- to cerebellum
- to spinal cord
- to medial longitudinal fasciculus
what is a function of the vestibular pathway?
-maintain oculovestibular balance
how is testing done for the vestibulocochlear nerve?
auditory/hearing test
what are the 4 functional components of the facial nerve?
- taste
- parasympathetic (salivary)
- sensory (small area behind ear)
- motor (facial expression)
which CNs are involved in the taste pathway?
- facial nerve
- glossopharyngeal
- vagus
what is the result of lesions involving the facial nerve?
-ipsilateral paralysis of facial muscles
what are the two disorders associated with facial nerve lesions?
- peripheral facial nerve (bell’s palsy)
2. central facial nerve (supranuclear palsy)
what does the abducens nerve do?
- strictly motor nerve
- to one muscle in the eye
what happens if the abducens nerve is lesioned?
-medial strabismus: ONly the affected eye does not abduct
what are the 2 sensory pathways?
- ML
- Spinothalamic Tract
what is the motor pathway?
corticospinal tract
what is the substantia nigra?
part of basal ganglia
what is the function of the trochlear nerve?
- when eye is turned medially, eye is depressed
- when eye is turned laterally, the superior oblique intorts the eye
what is a sign of a trochlear nerve lesion?
double vision looking down stairs
what are the 2 components of the oculomotor nerve?
- motor: innervates eye lid, ocular muscles except LR, SO
2. parasympathetic: preganglionic parasympahtetic innervasion
what is oculomotor nerve palsy?
-squint
-eyelid retracted
-dilated pupil
(all ipsilateral)
