spinal cord general
where the spinal nerves exit the vertebral canal and extend to the periphery
intervertebral foramena
most superficial meninge and its characteristics
dura mater - dense irregular connective tissue
these three structures compose each half of the white matter
dorsal (posterior) column
ventral (anterior) column
lateral column
__ pairs of cervical, __ pairs of thoracic, ___ pairs of lumbar, ___ pairs of sacral, and __ pair of coccygeal nerves
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
innervates superficial neck structures, skin of neck, and posterior portion of head, with roots in C1-C4.
it also contains a nerve called ___ from C3-C5 that innervates the diaphragm and is crucial in what process?
cervical plexus
phrenic nerve --- crucial for breathing
these are the regions of the spinal cord
cervical, thoracic, lumbar, sacral, coccygeal
characteristics of the middle meninge --- arachnoid mater
thin, avascular, simple squamous epithelial cells, network of collagen and elastin
these three structures compose each half of the gray matter
ventral (anterior) horns
lateral horns
four pairs of nerves exit the spinal column through this whole in the sacrum, while the rest exit through these spaces
four pairs through sacral foramina
rest of pairs through intervertebral foramina
roots of brachial plexus.
__ trunks, ___ divisions, __ cords, and __ branches.
each branch is corresponds to the nerve, and indicates the structures it innervates, what are they?
C5-T1
3 trunks, 6 divisions, 3 cords, 5 branches
axillary nerve
radial nerve
musculocutaneous nerve
median nerve
ulnar nerve
this is the number of spinal nerves present within the spinal cord
31 pairs
deepest layer of the meninges, and reason it's tight to the spinal cord
pia mater
adhered to spinal cord with blood vessels
these structures bridge their respective halves of white and gray matter
white commissure
gray commissure
___ surrounds a spinal nerve and is made up of dense connective tissue, ___ holds the fascicle together, ___ separates axons within a fascicle from one another
perineurium
endoneurium
the lumbar plexus has roots in this region (1)
these major nerves within the lumbar plexus supply parts of the lower limbs including lateral abdominal walls and external genitalia (2)
1) L1-L4
2) obturator and femoral
the physical structures of which the spinal cord extends include these at the start and finish, respectively
foramen magnum (where medulla oblongata ends)
L2 (most inferior rib on ribcage) **
* nerves extend out further but not in spinal cord
these come from small extensions of the pia mater and connect it to dura mater, as well as help to anchor the spinal cord laterally
denticulate ligaments
bundles of axon that make up nerve tracts, and the direction and characteristics of these neurons
fascicles
ascending and descending, myelinated axons
spinal nerves arise from these along the dorsal and ventral surfaces of the spinal cord. there are about ___ of these.
the combination of these two things form the spinal nerve as they pass through the subarachnoid space and pierce the arachnoid mater
rootlets
6-8
dorsal and ventral roots
this plexus is composed of sections L4-S4 (1) and contains two major nerves (2) which are bound together to form the sciatic nerve.
the sciatic nerve supplies large portions of the lower limbs including ___ (3)
1) sacral plexus
2) tibial and common fibular (peroneal) --> combine to form sciatic nerve
3) muscles and skin of lower limbs
the names of the enlargements and the reason they occur, the inferior tapering of the spinal cord, and "tether" that prevents superior movement, respectively
conus medullaris
filum terminale
order of the spaces within the meninges from superficial to deep, and their respective characteristics
subdural space
subarachnoid space --- between arachnoid and pia mater, continuous with brain, contains CSF
epidural space --- contains fat, blood vessels, and connective tissue, holds spinal cord in place
dorsal (posterior) --- sensory (IN), interneurons (in dorsal root ganglia)
lateral --- autonomic nervous system, thoracic and lumbar regions only
ventral (anterior) --- motor (OUT) to affect somatic system (and therefore skeletal muscle)
a spinal nerve splits into dorsal and ventral ___.
what are each of their functions?
ramuses (rami)
dorsal rasmus --- innervates deep muscles of the trunk responsible for movements of the vertebral column
ventral rasmus --- thoracic region (T2-T12) form intercostal nerves, remaining form roots of plexuses
the coccygeal plexus is composed of this spinal region (1)
it also contains muscles of this body region (2)
and carries sensory information from the skin covering this bone (3)
1) S5-Co
2) pelvic floor
3) coccyx