Embryonic Development Pt. 2

Afferent peripheral fibers

convey neural impulses to the CNS from the sense organs (ex: the eyes) and from sensory receptors in various parts of the body (ex: skin)

Efferent motor fibers

convey neural impulses from the CNS to effector organs (muscles and glands)

describe the formation of spinal nerve roots

rootlet, roots, spinal nerve root

what fibers are found in roots?

only motor OR sensory

what fibers are found in spinal nerve roots?

both motor and sensory

what do spinal nerves arise from the spinal cord as?

rootlets

rootlets converge to form ___ or ___ roots

anterior (ventral/motor) and posterior (dorsal/posterior)

roots converge to form ___

spinal nerves (aka spinal nerve roots)

when existing the vertebral canal, spinal nerves immediately split into ___ or___

anterior primary rami and posterior primary rami

Why are terms motor nerve and sensory nerve relative to majority of fiber types?

Nerves that supply muscle and sensory information also contain the other fiber that contribute to relating proprioceptive information, pain and serve smooth muscle

posterior primary rami

no plexuses form and innervate the deep muscles of the back and overlying skin in a segmental pattern

posterior primary rami are ___ of motor and sensory fibers

mixed

why are posterior primary rami mixed with sensory and motor fibers?

it comes directly from the spinal cord

why does the posterior primary rami not merge to form nerve plexuses?

the ribs are blocking the formation

anterior primary rami

forms plexuses to innervate anteriorly including limbs

where is a plexus not found in regards to anterior primary rami?

in the thoracic spine because of the ribs

limb innervation

formed from somatic nerve plexuses that form new multi segmental peripheral nerves

plexuses and rami directly innervate skin and musculature as ___

peripheral nerves

conus medullaris

end of spinal cord

cauda equina

collection of lumboscaral nerve roots that extend inferior to the end of the spinal cord

filum terminale

continuation of the dura, pia and glia connecting the end of there spinal cord with the coccyx

segmental innervation

spinal nerve roots that exit the spinal cord (ex: C1, C2, C2...)

peripheral nerve innervation

peripheral nerves are comprised of nerve roots and have names (ex: Femora;, obturator, sciatic...)

peripheral nerve root lesion

multiple spinal segments are affected

spinal nerve root lesion

single spinal segment is affected

ASIA scale indicates ___

somatic innervation

T or F, ASIA scale is used for peripheral innervation

FALSE

2 types of spinal cord injury

complete or incomplete

everything below the level of injury is ___ or ___

incomplete and complete

spinal nerve root injury

damage to a specific spinal segment

if a specific spinal cord segment is damaged ___

everything innervated is impaired/gone

peripheral nerve injury

damage is on the peripheral nervous system

___ peripheral nerves are damaged

specific

if peripheral nerve is damaged ___

everything the nerve innervates is impaired/gone below the level of the lesion

to test nerve roots, use ___

dermatomes, myotomes and deep tendon reflexes

to test peripheral nerves, use:

peripheral cutaneous map and MMT innervated solely by the suspected peripheral nerve