Nerve Supply of the Body Wall Flashcards
Which nerves supply the body wall as a whole
12 thoracic spinal nerves and first lumbar spinal nerve
end of the spinal cord
ends at L1as conus medullaris
Cauda equina continues after
where does a spinal nerve begin
where sensory and motor roots of spinal cord
anterior root vs posterior root
anterior is efferent - motor neurons
posterior is afferent - sensory neurons, ganglion present where cell bodies are concentrated
why does the anterior root of a spinal nerve have no ganglion
motor neuron cell bodies are in the grey matter of the spinal cord
what does a spinal nerve branch into
what do they supply
anterior and posterior ramus
supply front and back, ant and pos regions supplied by that nerve
where do spinal nerves emerge from the vertebral column
intervertebral foramen between pedicles
three layers of spinal meninges from outer to inner
Dura matter
Arachnoid matter
Pia matter
Denticulate ligaments role
prevent lateral movement of spinal cord
meningitis
inflammation of meninges
Dura mater and epidural space
tough fibre (dense collagen)
epidural space between dura matter and vertebral canal, anaesthesia
arachnoid and subarachnoid space
between dura and pia
subarachnoid space is filled with CSF
location of lumbar punctures (medical test)
pia mater
elastic and collagen fibre bound to neural tissue
organisation of spinal cord
inner grey matter with H shaped horns (projections towards outer surface)
median white and grey commissures
columns of white matter
anterior fissure and posterior sulci
what do motor fibres connect
muscles to lower motor neuron in ventral horn of spinal cord
what do sensory fibres connect
skin and deep tissues to sensory neuron in dorsal root ganglion
rami communicans
point of connection between pre-ganglionic fibre (ramus) and sympathetic trunk
post ganglionic sympathetic fibres
connect sympathetic trunk to organs
rejoin spinal nerve and are distributed via dorsal or ventral ramus to body wall
what do sympathetic fibres supply in the skin
blood vessels
sweat glands
arrectores pilorum
anterior ramus
each runs a separate course forward
supplies the skin muscles and serous membranes of thoracic and abdominal walls
some also supply limbs
dorsal ramus
passes backward and supplies muscles, bones, joints and skin of the back
overlap of thoracic nerves
distribution of ventral rami is segmental
but overlap is so great that the section above and below is needed to complete anaesthesia and paralysis of the middle one
dermatome
segment of skin innervated by a specific spinal nerve
why does shingles show up only on one dermatome
virus reactivation travels to the skin retrogradely from the DRG
