neuro 22 Flashcards
anterior gray matter
alpha motor neurons and motor fibers innervation skeletal muscles
in the lateral portion of the SC white matter
descending corticospinal tract
where does the CST cross
in he medulla
where does the CST synapse?
on alpha motor neurons in the anterior horn
dorsal columns do what
ascending tracts that mediate joint position sense
where do dorsal columns cross
the brainstem
where does the spinothalamic tract run?
anterolateral
what info does the spinothalamic tract carry?
pain and temp
where does the Spinothalamic tract synapse?
come into the SC and then synapse within two levels and then cross the cord an dascend contralateral to the limbs from which they originated
motor nerve roots
anterior in the SC
sensory nerve roots
posterior in the SC
where do the CERVICAL nerve roots exit the canal?
just above the corresponding vertebrae
why is there no C8 vertebra?
C8 nerve exits just above the T1
does C1 have sensory fibers?
nope
below the cervical region, where do the nerves exit the canal?
below their corresponding vertebal bodies
the corresponding level of the cord itself is typically where in relation to the root?
the level of the cord is typically a few bony levels above the root; for example, the T10 cord may lie adjacent to the T8 vert
where does the spinal cord ent?
L1 vertebral level
where do the dorsal columns cross?
brainstem
where does the spinothalamic tract cross?
in the cord, near the level of entry
transection at what spinal cord level gives you respiratory insuff
above C3-C5; and Horner’s may also develop due to transit of symp fibers up here
abdominal reflexes are lost with lesions above what?
T6
bowel and bladder dysfunction may follow lesions above what?
sacral spinal cord level
intramedullary
within the SC
common causes of cord compression
bony lesions from metastatic cancer, esp breast and prostate
Brown-Sequard syndome
hemicord
loss of proprioception and light touch ipsilateral, motor ipsi, and pain and temp contra
hemicord lesion
what does a central SC lesion affect?
spinothalamic tract fibers crossing at the level of the lesion; deficits in pain and temp are bilateral and over several segments
what is a “dissociated” sensory loss
pain and temp sesation are affected but proprioception ang light touch are not; seen in central cord lesions
syringomyelia
expanison of the potential fluid space in the center of the SC, usually over several levels
cape-like loss of pain and temp sensation
syringomyelia