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Flashcards in Pons Deck (21)
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3 CNs that Come out Pontomedullary Junction (medial lateral)

VI, VII, VIII. Motor->sensory


14 Items in Pontomedullary Pons

Corticospinal tract (w/ corticopontine and bulbar fibers)
Vestibular and Cochlear N.s (VIII)
Superior olive
Inferior cerebellar peduncle
Vestibular nuclei
Trigeminothalamic, spinothalamic tracts and medial lemniscus
Ventral and dorsal cochlear nucleus
Spinal tract/nucleus of V
Central tegmental tract
Medial longitudinal fasciculus
Trapezoid body


Notable Point About Sensory Fibers in Pons

Medial lemniscus and spinothalamic/trigeminothalamic tracts move close to each other so lesion can knock out all contralateral sensory


Corticopontine Fibers

Synapse in pons and cross into cerebellar peduncle


Corticobulbar Fibers

CN going to pretty much any CN nucleus (motor)


Notable Point About Medial Longitudinal Fasciculus

Stays where it is in middle posterior


Trapezoid Body

2nd order neurons for hearing crossing


3 Nuclei of Caudal Pons

Facial, abducens, and spinal nucleus of V


Notable Point About VI and VII

VI goes straight out from nucleus, but VII goes back and wraps around VI nucleus and then goes out more laterally, so lesion to VI nucleus will also take out VII


14 Items in Middle Pons

Corticospinal/pontine/bulbar tracts
Pontocerebellar tract (crossing)
Medial lemniscus
Spinothalamic tract
Trigeminothalamic tract
Motor nucleus of V
Mesencephalic nuc of V
Main sensory nuc of V
Locus ceruleus
Medial longitudinal fasciculus
Raphe nucleus


Locus ceruleus

Sends NE-ergic neurons throughout brain to kinda oppose Raphe


Sensory Path of V

Come in though V branches
Synapse at trigeminal ganglion
Spinal tract of V
Synapse at spinal nucleus of V (along w/ cutaneous from VII, IX, and X)
Decussate and go up trigeminothalamic tract
Synapse in thalamus (3rd order)
Go to postcentral gyrus in cortex


Motor Nucleus of V

Corticobulbar fibers (upper motor neurons) come down to innervate/synapse and give off ipsilateral motor neurons to innervation of 8 1st branchial arch muscles


Mesencephalic Nucleus

Brings in proprioceptive sensory from jaw, first order cell bodies like DRG but in CNS


4/5 Locations Vestibular Nuclei Project To

Spinal cord via vestibulospinal tracts
Eye motor nuclei via MLF
Cerebellum via inferior cerebellar peduncle
Ventral posterior nucleus of the thalamus (& postcentral gyrus of cortex)


Notable Aspect About Cochlear Nuclei

Don't get normal 2nd order decussation. Instead get bilateral projections - ipsi and contralateral. Lesions affect hearing on both sides


5 Sensory Tracts Through Pons

Medial lemniscus (gensens)
Spinothalamic tracts (pain/temp)
Lateral lemniscus (auditory)
Spinal tract of V (1st order sensory gen/pain/temp from face)
Trigeminothalamic tracts (2nd order sensory gen/pain/temp from face)


Lesion of V

Ipsilateral effects of all 8 muscles, and all sensation from face


Lesion of VI

Ipsilateral eye deviates medially (strabismus) and double vision (diplopia)


Lesion of VII

Ipsilateral facial muscle paralysis (+stapedius/stylohyoid/post belly digastric)
Lose parasymp to glands besides parotid
Bell's palsy


Acoustic Neuroma

Lesion in internal acoustic meatus, can lose VIII and VII