MHS Module 6- spinal cord p4

explain the spinal cord:

housed within protective membranes (meninges) and vertebral column

carries sensory and motor information between brain and most other parts of the body

explain anatomy of spinal cord:

from brain to vertebrae L1 and L2

has 4 regions

has bilateral symmetry

45 cm long

what are the 4 regions of the spinal cord:

cervical

thoraic

lumbar

sacral

explain the grooves of the spinal cord:

divides spinal cord into left and right:

• posterior median sulcus

  • anterior median fissure - a deeper anterior groove

explain central canal

runs through the whole spinal cord containing cerebrospinal fluid

what are components of the distal end of the spinal cord:

conus medullar is

cauda equina

filum terminale

explain conus medullar is:

tapered, conical end of cord below lumbar enlargement

explain cauda equina:

nerve roots extending below conus medullaris

looks like a horse tail, hence the name

explain the filum terminale

thin thread of fibrous tissue at end of conus medullaris

attaches to coccygeal ligament

explain the spinal roots

2 branches from spinal nerves:

• anterior (ventral root)

• posterior (dorsal root)

spinal nerve roots divide into rootlets before entering or leaving the spinal cord

explain anterior ventral root:

contains axons of motor neurons

explain posterior dorsal root:

axons of sensory neurons

explain the spinal ganglia:

contain cell bodies of sensory neurons that form the posterior root

located between pedicles of adjacent vertebrae

what is the cervical enlargement:

supplies skin and muscles of shoulder and upper limbs

what is the lumbosacral enlargement:

supplies pelvis and lower limb

explain spinal nerves:

formed by union of posterior and anterior roots

each has white ramus communicant and grey ramus communicant that innervate glands and smooth glands

explain mixed spinal nerves:

contain both afferent efferent fibres

what do spinal nerves divide into and explain each type:

divide into rami:

• posterior ramus supplies skin/muscles of back

• anterior ramus supplies most of body wall, skin, limbs

name spinal nerves:

C1 runs above first cervical vertebra

C8 runs below seventh cervical vertebra

All others named for vertebrae above

T1 is below first thoracic vertebra

name the spinal meninges:

same as cranial meninges:

• dura mater

• arachnoid mater

• pia mater

functions of spinal meninges:

protect spinal cord

carry blood supply

explain arachnoid trabecular:

network of collagen/elastic fibers between arachnoid membrane

what does the lumbar puncture do?

withdraws CSF from subarachnoid space

where are blood vessels found in the spinal meninges:

surface of Pia mater within subarachnoid space

explain paired denticulate ligaments:

anchor Pia mater to dura mater

prevent lateral movement of spinal cord

what is grey matter?

cell bodies of neurons, neuroglia and unmyelinated axons

what is white matter:

myelinated and unmyelinated axons

how is grey matter in the CNS organised and name each region:

posterior horns

anterior horns

lateral horns

gray commissures

what is posterior horns:

somatic and visceral sensory nuclei

what is anterior hornsi:

somatic motor nuclei

what are lateral horns:

thoracic and lumbar segments & visceral motor nuclei

explain gray commissures:

narrow bands of grey matter around central canal