spinal cord and spinal nerves Flashcards
sensory axons
dorsal root
primarily interneurons and sensory neuron axons
posterior horns
motor neuron axons
ventral root
dorsal median sulcus and ventral median fissure divide cord on either side of canal
central canal
cell bodies of somatic motor neurons and some interneurons
anterior horns
(thoracic and lumbar only) ANS motor cell bodies
lateral horns
located in the center of the spinal cord and shaped like a butterfly or the letter H.
gray matter
posterior projections of the gray matter that contain primarily interneurons and the axons of sensory neurons
dorsal horns
anterior projections of the gray matter that contain the cell bodies of somatic motor neurons and some interneurons
ventral horns
small lateral projections that are present only in the thoracic and lumbar regions of the gray matter. when present, they contain the cell bodies of motor neurons of the autonomic nervous system
lateral horn
the cross bar of the H that surrounds the central canal
gray commissure
forms the outer region of the spinal cord and is composed of myelinated and nonmyelinated axons organized into tracts
white matter
the anterior, more open of the two grooves that partially divide the spinal cord into left and right halves
anterior median fissure
the posterior, shallower of the two grooves that partially divide the spinal cord into left and right halves
posterior median sulcus
each side of the spinal cord has three funicular, dorsal, lateral, and ventral funiculus, which are further divided into tracts
white columns
muscular branches: deltoid and teres minor muscles. cutaneous branches: some skin of the shoulder region
-posterior cord (C5-C6)
axillary
muscular branches: flexor muscles in the anterior arm. cutaneous branches: skin on anterolateral forearm
-lateral cord (C5-C7)
musculocutaneous
muscular branches to flexor group of anterior forearm; intrinsic muscles of lateral palm and digital branches to the fingers. cutaneous branches: skin of lateral two-thirds of hand on ventral side and dorsum of fingers 2 and 3
-by two branches, one from medial cord (C8, T1), and one from the lateral cord (C5-C7)
median
muscular branches: flexor muscles in anterior forearm; most intrinsic muscles of hand. cutaneous branches: skin of the posterolateral surface of entire limb
-posterior cord (C5-C8, T1)
radial
rhomboid muscles and levator scapulae
-branches of C5 rami
dorsal scapular
serratus anterior muscle
-branches of C5-C7 rami
long thoracic
teres major and subscapularis muscles
-posterior cord; branches of C5 and C6 rami
subscapular
shoulder joint; supraspinatus and infraspinatus muscles
-upper trunk (C5, C6)
suprascapular
pectoralis major and minor muscles
-branches of lateral and medial cords (C5-T1)
pectoral
serve the skin and musculature of the posterior body trunk at their approximate level of emergence
dorsal rami
bundles of fibers that connect the spinal nerves to the sympathetic chain
rami communications
a bundle of nerve fibers that cross the midline of the spinal cord or brain to connect the two hemispheres
white commissure
where does the spinal cord end in adults?
in the lower back between the first and second lumbar vertebrae
what structure does the spinal cord end in?
conus medullaris
what is a plexus
a network of nerves or vessels in the body
where are the plexuses located?
cervical, brachial, lumbar, sacral, and coccygeal
what are intercostal nerves?
nerves that run between the ribs and are part of the somatic nervous system
