Spinal cord, spinal nerves and ANS Flashcards
general features/ extends to: spinal cord
- cylindrical, flattened antero-posteriorly
- extends to L2 (adult) and L3-4 (newborn)
- ends: conus medularis -> filum terminale extends (extension of pia mater)
spinal cord: enlargements and nerves form
lumbar, sacral and coccygeal nerves = cauda equina
cervical (C4-T1)
lumbar (T9-T12)
grooves of spinal cord:
anterior median fissure
posterior median suclus
spinal cord: grey matter
butterfly shaped: grey commissure connects two sides of grey matter
- sensory and motor nuclei (central canal)
anterior grey horn: somatic motor nuscle
posterior grey horn: cell bodies/ axons of interneurons/ axons of sensory neurons
lateral grey horn: autonomic motor nuclei (in thoracic, upper lumbar and sacral regions)
spinal cord: white matter
anterior, posterior and lateral white columns contain ascending sensory, descending motor tracts
spinal nerve: general features
31 pairs
- emerge from spinal segments
- pass through invertebral formamina
- all mixed
list pairs of spinal nerves in each region:
cervical (8) thoracic (12) lumbar (5) sacral (5) coccygeal (1)
connective tissue surrounding: nerve fiber
endoneurium
connective tissue surrounding: fasciculi
perineurium
- group of nerve fibres
connective tissue surrounding: nerve
epineurium
- 50% of nerve, contains blood vessels and lymphatics
spinal nerves arise as:
anterior (axons of multipolar motor neurons) and posterior (sensory unipolar neurons) rootlets
rootlets converge to form:
anterior/ posterior roots (posterior root ganglion- contains cell bodies of sensory neurons)
roots converge to formr;
spinal nerve trunk (mixed)
spinal nerve trunk divides into:
anterior/ posterior ramus
and no. of smaller branches (meningeal branches, rami communicantes)
posterior ramus:
deep muscles and skin of posterior surface of trunk
anterior ramus:
limbs and skin and muscles of lateral and anterior trunk
list general flow of spinal nerve:
ant/post rootlets -> ant/post roots -> mixed spinal nerve trunk -> ant/post ramus and smaller branches
define/ list all spinal plexuses:
network of axons made by anterior rami of spinal nerves
cervical, brachial, lumbar, sacral
plexus general features: cervical
roots and nerves loopy
plexus general features: brachial
roots, trunks, anterior/ posterior division, cords, branches
plexus general features: lumbar
roots, anterior/ posterior division
plexus general features: sacral
roots, anterior/ posterior division