Nerve supply of the back Flashcards
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functions of spinal cord
- relay center for incoming sensory info through dorsal roots and horn
- conduit for ascending (afferent) and descending (efferent) pathways
- origin of LMNs: commands to muscles of body from ventral horn
spinal cord is protected by ____
vertebral column
spinal cord is covered by ____
meninges
spinal nerves exit through the ____
intervertebral foramen
what are meninges?
connective tissue membranes
layers of meninges
dura
arachnoid
pia
spaces of meninges
- subarachnoid
- subdural
- epidural
subarachnoid space is filled with ____
cerebrospinal fluid and arteries
subdural space is the location of ____
veins
epidural space is filled with ____
fat
adult spinal cord is continuous with ____
medulla
adult spinal cord length
42-45cm
what is the conus medullaris?
conical distal end of spinal cord at L1-L2 vertebral level
the spinal cord has ____ and ____ enlargements
cervical and lumbar enlargements
cauda equina
nerve roots extending beyond conus medullaris
Bell-Magendie Law
- sensory info goes into spinal cord via dorsal roots of spinal nerves
- motor “commands” leave spinal cord via ventral roots of spinal nerves
spinal cord segments at different levels
- cervical: 8 segments
- thoracic: 12 segments
- lumbar: 5 segments
- sacral: 5 segments
- few coccygeal
Ventral horn contains…
Cell bodies of alpha & gamma motor neurons (LMN)
Intermediolateral gray contains…
- T1-L2 = preganglionic sympathetic neurons
- S2-S4 = preganglionic parasympathetic fibers
Dorsal horn contains…
Sensory cell bodies
White matter
dorsal columns (sensory)
Fasciculus gracilis (medial) & Cuneatus (lateral)
white matter
Ventral & lateral columns
Tracts overlap for several functions (mostly motor)
Most structures of body wall & limbs are innervated by ____
Spinal nerves
Spinal nerves exit the spinal canal through ____
Intervertebral foramen
