Dermatomes/myotomes Flashcards
(26 cards)
where does somite come from
paraxial mesoderm
anterior portion of somite becomes what
sclerotome
the somitic mesoderm separates into
dermatome, myotome, sclerotome
myotome separates into what
epimere (dorsal) and hypomere (ventral)
what do the epaxial muscles become
deep muscles of back such as erector muscles and spinal muscles
hypaxial muscles make up
the lateral and ventral body wall
sclerotome ends up wrapping around the notochord to form what
verterbrae
notochord contributes to the
nucleus pulposus of the intervertebral disk
dermatome is
the area of skin supplied with afferent nerve fibers by a single posterior spinal root
sensory part
afferent - dorsal root (the cell bodies are in the dorsal root ganglion)
motor part
efferent - ventral root
from posterior to anterior what are the divisions of the cord
somatic and visceral (sensory) and then autonomic and somatic (motor)
dermatome
unilateral area of skin innervated by the sensory fibers of a single spinal nerve
myotome
unilateral muscle mass receiving innervation from the fibers conveyed by a single spinal nerve
the posterior ramus innervates what
epaxial muscles of the back
the anterior ramus innervates what
hypaxial muscle
why is the anterior ramus larger than the posterior one
there are more muscles and tissues to innervate for a dermatome/myotome anterior to the spine
what is the difference between a segmental arrangement and plexus
segmental nerves form a more linear arrangement
plexus arrangement have more overlapping nerves
-since they are overlapping areas are less sensitive to deficits
autonomic plexuses control what
visceral sensory and visceral motor functions
what is the cervical plexus made of? what does it do?
C1-C4, innervates anterior neck; skin of head neck and shoulders
lumbosacral plexus
L2-S3
what branch is c6-t1
median n.
what branch is c8-t1
ulnar n.
what branch is c5-t1
radial n.
