Spinal Cord
lumbar enlargement
extends through lumbar and sacral parts of the spinal cord and innervates the lower limbs
median nerve
innervates flexor muscles
musculotaneous nerve
innervates flexors; come off lateral cord
integration center
interprets input and elicits response
femoral nerve
posterior division of lumbar plexus
brachial plexus
spinal nerves C5-T1; supply upper limbs and pectoral girdle
lumbar plexus
spinal nerves L1-L4; subdivided into anterior (obturator) and posterior division (femoral)
sacral plexus
spinal nerves L4-S4;
spinal cord
the cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brain, with which it forms the central nervous system
reflex arcs
the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between (PNS > CNS > PNS)
axillary nerve
diverges from posterior cord
common fibular nerve
L4-S2; posterior division of sciatic nerve
tibial nerve
L4-S3; anterior division of sciatic nerve
obturator nerve
anterior division of lumbar plexus
dermatomes
area of skin innervated by all the sensory neurons of a single spinal nerve
sacral spinal nerves
bowel, bladder, sexual function, and feet (PNS)
lateral cord
brachial plexus division, C5-C7 (#5)
posterior cord
brachial plexus division, C5-T1 (#17)
medial cord
brachial plexus division, C8-T1 (#18)
thoracic spinal nerves
chest and abdominal muscles (PNS)
motor neuron
conducts efferent impulse to effector
anterior (ventral) root
contains motor neurons
posterior (dorsal) root
contains sensory axons only
posterior root ganglion
contains sensory neuron (cell) bodies
paraplegia
damage btw T1 and L2; lower limbs
quadriplegia
damage in cervical region; all limbs
cauda equina
group of axons that project ineriorly from the spinal cord
gray commissure
horizontal bar of gray matter that surrounds central canal; connects left and right sides of the gray matter
sciatic nerve
largest and longest nerve in sacral plexus
anterior (ventral) horns
left and right anterior masses of gray matter
posterior (dorsal) horns
left and right posterior masses of gray matter
lumbar spinal nerves
leg muscles (PNS)
cervical plexus
located deep on each side of the neck, immediately lateral to cervical vertebrae (C1-C4). innervates anterior neck muscles, head, and shoulders
cervical enlargement
located in the inferior cervical part of the spinal cord, contains the neurons that innervate the upper limb
paralysis
loss of motor function
conus medullaris
marks the official end of the spinal cord proper
effector
muscle or gland that responds
cervical spinal nerves
nerves to the head, neck, diaphragm, and arms (PNS)
lateral horn
occurs in T1-L2, contain cell bodies of autonomic motor neurons
phrenic nerve
originated from C4 and some contributing axons of C3 and C5
radial nerve
posterior to musculotaneous
shingles
reactivation of chickenpox; virus invades dorsal root ganglia of spinal cord
central cannal
runs the entire length of the spinal cord and contains cerebrospinal fluid (CSF)
sensory neuron
transmit afferent impulse to CNS
