Lab Manual 4 Flashcards
which vertebra level does the spinal cord end
level L1/L2
where is the lumbar puncture located
L3-L5
what are the spinal nerves?
small, white, cylindrical structures occurring in pairs about every 1.5 inches along the length of the cord
denticulate ligaments
the short bands of fibrous pia mater extending along the spinal cord on each side, in-between the dorsal and ventral roots
rootlets
small groups of axons that combine to form the nerve roots
- dorsal/posterior roots and ventral/anterior roots
what do dorsal/posterior roots do
carry sensory impulses to the spinal cord
what do ventral/anterior roots do
carry impulses from spinal cord to body
where is the spinal cord thicker
at the neck and end of the cord (cervical and lumbar enlargements)
why is the spinal cord thicker at the neck and end of the cord
large group of nerves leave the cord to seve the arms and legs
where is there more gray matter than white matter in the spinal cord
s > l > t > c
where is there more white matter than gray matter
c > t > l > s
conus medullaris
the most caudal end of the spinal cord
filum terminale
an inferior extension of the pia mater beyond the conus medullaris that anchors the spinal cord to the coccyx at the very bottom of the vertebral canal
cauda equina
a bundle of spinal nerves - 2L - 5L, 1S - 5S, and the coccygeal nerve
lumbar cistern
a subarachnoid space inferior to the conus medullaris
- cauda equina occupies it
where are spinal taps conducted
lumbar cistern
two subdivisions of autonomic nervous system
sympathetic nervous system, parasympathetic nervous system
where are sympathetic neurons located
thoracic and upper lumbar spinal cord segments
what do sympathetic neurons connect to
post-ganglionic neurons
where are post-ganglionic neurons located
just outside of the vertebral column running in a connected chain along the bone column
- part of the PNS
what do sympathetic chain ganglia neurons project to
target organs all over the body
where are parasympathetic neurons located
in the brainstem and sacral spinal cord
where do the parasympathetic neurons project
out of the CNS far away from the spinal cord to post-ganglionic neurons located near or in their target organs in the body
where are parasympathetic post-ganglioni neurons found
in or near their target organs
which parts of the spinal cord are white matter
dorsal, lateral, and ventral columns (aka posterior funiculus, lateral funiculus, and anterior funiculus)
which parts of the spinal cord are gray matter
posterior (dorsal) horn, lateral horn (intermediate gray), & anterior (ventral) horn
Westphal’s sign
the absence or decrease of the knee tap reflex; indicates spinal cord nerve damage
what opposing muscles are required to produce the foot swing respose
contraction of the quadriceps and the inhibition of the opposing hamstring flexor muscle
which spinal neurons mediate the knee jerk reflex
L2 - L4 spinal neurons
two point distinction
the ability to discern that two nearby objects touching the skin are truly two distinct points, not one
what is the medical use for two-point discrimination
testing for deficits in tactile perception and injury to the dorsal column medial lemniscus (DCML) ascending sensory neuron tracts
