Comparative Anatomy of the Spinal Cord

dorsal root entry to spinal cord and synapse and cell body

dorsolateral sulcus to dorsal root of grey matter

cell body in the spinal ganglion of the dorsal root

ventral root exit and synapse location

ventrolateral sulcus exit

ventral horn synapse (multipolar so cell body located here)

what are the techcnical wrods for above and below spinal cord

epaxial - above

hypaxial - below

vertebrae vs spinal segments numbers

c7 t13 l7 s3 c5-23

c8 t13 l7 s3 c5

what are the two factors of locations of the spinal cord

where the nerves leave in relation to the vertebrae

wehre the spinal segments are in relation to the vertebrae

what are the two exceptions in terms of where the nerves leave

C1 leaves through the lateral vertebral foramen of the atlas vertebra

S1-3 leave through S1

where and why do the nerves change from cranial to caudal exit

they were cranial due to C1 leaving atlas so C2 was cranial to C2 and so on

then C8 leaves from cranial to T1 because there is no C8 vertebra so then T1 spinal nerves has to leave caudally to the T1 vertebrae

note that t1 spinal segment is different to t1 spinal nerves so make sure you differentiate between them

ok

where are the two intumescences

brachial plexus - C6-T2

lumbar plexus - L5-S1-S3 - but nerve segments are at L4-5

what are the three weird things at the end

conus medullaris - tapered end of the spinal cord

cauda equinae - continuation of spinal nerves past the end of the spinal cord but in the bit where the spinal cord lives

filum terminale - neuroglial and ependymal continuation of the spinal cord, but just CT to attach to the caudal vertebrae for stabilisation of the spinal cord

where does the spinal cord start and end

start - foramen magnum

end - L6-L7

When do vertebrae stop corresponding to spinal segments?

L2-L3

layers of PNS nerves

endoneurium - perineurium - endoneurium