Lecture 6 Flashcards
spinal cord
continuation of the brainstem, extends from foramen magnum at the base of the skull to the L1/L2 vertebrae
verterbrae arranged in 5 regions
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacrum
- 4 coccyx
- sacrum and coccyx fused together
atlas
first vertebra of the cervical region b/w base of the skull & C2 ( axis )
axis
second vertebra of cervical region b/w atlas ( C1 ) & C3
function of atlas and axis
- support the head on the lower cervical spine providing for mobility in extension, rotation, flexion
- specialised to allower a greater range of motion than other vertebrae
comparison of vertebrae
look at notes lol
spinous processes
bony projections off the posterior of each vertebrae
* provides a point of attachment for muscles and ligaments of the spine
vertebral foramen
bony hollow opening of vertebrae through which all spinal nerve roots run
SC anatomy
- begins at the occipital bone
- ends as cauda equina
- provides 2-way communication b/w CNS & PNS
Cervical enlargement
- SC expansion corresponds to arms
- C4 - T1, max circumference 38mm
- nerves serving arms emerge here
Lumbar enlargement
- SC expansion corresponding to lower limbs
- T11 - L2 , max circumference 33mm
- nerves serving lower limbs emerge here
cauda equina
collection of nerve roots at the inferior end of the vertebral canal wall
cauda equina syndrome symptoms
- low back pain, radiating down the legs
- numbness around anus
- loss of bladder/bowel control
cauda equina syndrome causes
- compression
- spinal stenosis ( narrowing )
- disc herniation
- abscess formation
SC internal anatomy
- grey matter inside, white matter outside
- 2 lenghth wise grooves that divide cord into left and right
1. ventral ( anterior ) median fissure
2. dorsal ( posterior ) median sulcus - gray comissure connects left & right grey areas
Grey matter
- has large number of neurons present, allows it to process info
- has 4 main columns
1. dorsal horn - contains interneurons; receives somatosensory info from body to brain
2. ventral horn -motor neurons that exit SC to innervate skeletal muscle
3. intermediate & lateral horn - lateral responsible for regulating ANS
spinal nerves
- pass in and out superior to the corresponding vertebrae via intervertebral foramen
- supply all areas of the body except head & neck regions ( cranial nerves )
31 pairs of spinal nerves
- 8 cervical nerves
- 12 thoracic nerves
- 5 lumbar nerves
- 5 saccral nerves
- 1 coccygeal nerve
white matter
- contains bundles of nerve axons
- allows communication with CNS
- may be ascending or descending
descending pathways
deliver efferent impulses from brain to spinal cord
direct pathways - pyramidal tracts
- originate in motor cortex
- carry motor fibres to SC & brainstem
- responsible for volitional movements
- parkison’s disease
indirect pathways - extrapyramidal tracts
- originate in brain stem
- motor fibres to SC
- prevent unwanted movements
- huntington’s disease
- responsible for autonomic control of balance, posture
incomplete injuries
- central cord syndrome
- posterior cord syndrome
- anterior cord syndrome
- cauda equina syndrome
quadriplega
- injury in cervical region
- all 4 extremities are affected
paraplegia
- injury in lumbar, thoracic or saccral regions
- only 2 extremities affected
causes of SC injury
- assault
- sport
- tumours
- infection
- falls
- central cord syndrome
