Medulla Flashcards
(59 cards)
while cranial nerves can be found at some location within the medulla
8-12
closed medulla
-location
C1 to the caudal end of the 4th ventricle
nuclei within the closed medulla
inferior olivary nucleus or complex nucleus cuneatus nucleus gracilis hypoglassal nucleus spinal trigeminal nucleus (spinal nucleus of V)
tracts within the closed medulla
pyramids spinothalamic tracts (spinal lemniscus) ventral trigeminothalamic tract fasciculus cuneatus fasciculus gracilis medial longitudinal fasciculus (medial vestibulospinal tract) lateral vestibulospinal tract medial lemniscus internal arcuate fibers spinal trigeminal tract dorsal spinocerebellar tract hypoglossal nerve fibers
open medulla
-location
caudal end of 4th ventricle to the pontomedullary junction
nuclei within the open medulla
inferior olivary nucleus spinal nucleus of V hypoglossal nucleus dorsal motor nucleus of the Vagus nucleus ambiguus vestibular nuclei dorsal cochlear nucleus ventral cochlear nucleus
dorsal motor nucleus of the
Vagus
-sympathetic or parasympathetic
parasympathetic
what is within nucleus ambiguus
LMNs for CN IX and X
tracts within the open medulla
pyramids medial lemniscus hypoglossal nerve fibers ventral trigeminothalamic tract medial vestibulospinal tract (MLF) medial longitudinal fasciculus (MLF) lateral vestibulospinal tract inferior cerebellar peduncle olivocerebellar fibers lateral spinothalamic tract spinal trigeminal tract
CN XII
-function
motor nerve
supplies both intrinsic and extrinsic muscles of the tongue
CN XII
-LMN cell body location
hypoglossal nucleus
-near midline of medulla (ventral to the central or 4th ventricule)
CN XII
-LMN axon location
pass inferolateral to the medial lemniscus and pyramids
exit medulla as rootlets in the ventrolateral (preolivary) sulcus, adjacent to the pyramids
what comes out of the preolivary sulcus
CN XII fibers
CN XII UMNs
- name
- arise from…
- descend with _____ to ____
- synapse where?
corticobulbar fibers
arise from tongue region of precentral gyrus (primary motor cortex)
descend with the corticospinal tract to the medulla
most fibers cross midline in medulla and synapse in the contralateral hypoglossal nucleus
hypoglossal nucleus
- receives _____ sensory information from _____
- how does it receive this information
- this reflex pathway controlling the tongue is involved in…
receives indirect sensory information from solitary nucleus and sensory trigeminal nuclei
receives information via multisynaptic connections in the reticular formation
reflex pathway involved in swallowing, suckling, and chewing
solitary nucleus
-function in relation to CN XII
taste
sensory trigeminal nuclei
-function in relation to CN XII
bolus of food in the oral cavity
LMN lesion of the hypoglossal nerve or nucleus
- results in…
- clinical signs
results in paralysis and muscle wasting of both the intrinsic and extrinsic muscles of the ipsilateral side
clinical signs
-upon protrusion of the tongue, it deviates toward the side of the lesion due to unopposed action of the intact contralateral genioglossus muscle
-patients have difficulty with eating and speaking (dysarthria)
UMN lesion of the hypoglossal nerve
- where does it occur
- results in…
occurs at a level prior to the cross
results in weakness of only the extrinsic muscles (primarily genioglossus) on the side contralateral to the site of the lesion
which way will the tongue deviate if a UMN for CN XII is injured?
contralateral side
stroke of paramedian branch of anterior spinal artery may result in damage to…
hypoglossal nerve fibers
adjacent pyramid
medial lemniscus
ventral trigeminothalamic tract
stroke of paramedian branch of anterior spinal artery will produce what symptoms?
LMN symptom (ipilateral) UMN symptoms involving the pyramid (contralateral)
the combination of LMN and UMN signs that are seen on opposite sides of the neuraxis with injury to the paramedian branch of the anterior spinal artery occur where…
-this combo of Sx is called…
occur where a motor cranial nerve exits along the midline adjacent to the descending corticospinal fibers
combo of Sx is called an alternating hemiplegis
CN XI
- location of LMNs
- functions of LMNs in each location
nucleus ambiguus
-innervate a few of the laryngeal muscles (cranial component)
cervical levels of spinal cord (dorsal to ventral horn)
-innervate SCN and trapezius
