NAS WK6 - SPINAL CORD Flashcards
CNS OR PNS
spinal cord is CNS but spinal nerves are PNS
VERTEBRAL BODY
- anterior, weight bearing component of bone
- separated from other vertebral bodies by vertebral discs
VERTEBRAL ARCH
- joined to posterior surface of vertebral body by 2 pedicles
- roof of vertebral arch formed by R & L laminae fusing at midline
- transverse process projects laterally on each side of vertebral arch
- spinous process projects posteriorly & inferiorly from roof of vertebral arch
- superior & inferior articular processes join to similar processes on adjacent vertebrae
VERTEBRAL CANAL
- spinal cord lies in bony canal
- ANTERIOR WALL - formed by vertebral bodies & intervertebral discs
- LATERAL WALL - formed by vertebral arches
EXTRINSIC MUSCLES OF BACK
- move upper limbs & thoracic wall
- innervated by anterior rami of spinal nerves
INTRINSIC MUSCLES OF BACK
- maintain posture & move vertebral column
- innervated by posterior rami of spinal nerves
CERVICAL & LUMBAR ENLARGEMENT
enlargement of spinal cord due to more grey matter as has the spinal nerves that go to upper (cervical) & lower (L2-S3 lumbar) limbs
SPINAL NERVES
- emerge from vertebral canal between pedicles
- each nerve attached to spinal cord by posterior/dorsal root & anterior/ventral root
- after leaving vertebral canal, each spinal nerve divides into posterior/dorsal rami (small & innervate back) & anterior/ventral rami (large & innervate body except head)
DORSAL ROOT
- sensory neurones carrying info to CNS
- cell bodies of sensory neurones are clustered in dorsal root ganglion at distal end of dorsal root
VENTRAL ROOT
motor neurones carrying info away from CNS
VERTEBRAL LEVELS
- Cervical - C1-8
- Thoracic - T1-12
- Lumbar - L1-5
- Sacral - S1-5 (fuse to form C1)
- C8 & all other spinal nerves
CAUDA EQUINA
- terminal cluster of roots below end of spinal cord where posterior & anterior roots of lumbar, sacral & coccygeal nerves pass inferiorly to reach their exit points from vertebral canal
- from L2 - Coccygeal 1
FILUM TERMINALE
extension of pia mater & anchors spinal cord down to coccyx at bottom of vertebral column
how sensory receptors work
Sensory receptor sends signal into dorsal rami & then goes to dorsal root ganglia where there are cell bodies & then synapses into grey matter & by interneuron pathways it activates motor neurones in ventral grey horn & can go to dorsal rami
DERMATOME
- area of skin innervated by a single spinal nerve
- clinically relevant as we can test what damage has occurred at each spinal level by testing where each spinal nerve innervates