Lecture 18 Spinal Cord and Spinal Nerves Flashcards
vertebrae
bony structures that surround spinal cord
vertebral column
vertebrae stacked on one another
vertebral foramen
each individual vertebrae has an opening bounded ventrally/anteriorly by the body of the vertebra
vertebral canal
when you stack vertebral foramen holes on top of one another to create a canal where spinal cord is located
intervertebral foramina
spaces/openings between the vertebrae where spinal nerves will exit the vertebral canal and extend out to the periphery
numbering of nerves (C1, T1…) is based on
which level of the vertebral canal they exit through the foramina
why is the spinal cord shorter than the vertebral canal ?
spinal cord stops growing at age 4/5
vertebral column grows till age 18/22
how many pairs of spinal nerves are there?
31
Roles of spinal cord:
- communication between brain and PNS (below the head)
- provides pathway for nerve impulses
-sensory info will gather from periphery and enter spinal cord while motor info will go out into muscles from spinal cord
-integrate and produce responses. Determines where sensory info needs to go after its been collected from periphery and can create motor responses
spinal cord extends from _ to _
from foramen magnum (hole is base of skull) to L2 (same level as most inferior rib on ribcage)
What are the two enlargements on the spinal cord?
- Cervical - between C4 and T1
- Lumbosacral - between T9 and T12 vertebrae
associated w/ extra nervous tissue needed to supply additional structures of upper and lower limbs (muscles, bones, tissues that need to be supplied w/ neurons)
Corpus Medullaris
tip/end of spinal cord
Cauda Equina
hair like nature of nerves coming out of bottom of spinal cord
Filum Terminale
extension of the pia mater CT covering around the spinal cord. Anchors spinal cord to inferior part of vertebral column (coccyx). Acts as tether for spinal cord, stops any superior direction movement.
where do nerves supplying lower limbs exit? Then they course down through vertebral canal to exit via…
LS enlargement , foramina
Meninges in spinal cord?
- dura mater
- arachnoid space
- subdural space
- pia mater
- subarachnoid space
Epidural Space is:
space between periosteum (CT on bone) and the dura mater. Space filled w/fat, blood vessels, areolar CT. Helps protect and hold spinal cord in place.
- has pain receptors, epidural during pregnancy blocks these
Denticulate Ligaments
pia mater has small extensions of itself that move towards the dura mater
Filum Terminale
another extension of pia mater which extends to the coccyx, helps anchor the spinal cord longitudinally and prevents superior/inferior movement
what functions do all spinal nerve have?
motor and sensory
What columns are in outer white matter of the spinal cord?
two halves, 3 columns in each half
- each column is subdivided into nerve tracts (fasciculi) which allow info to be transmitted in an organised fashion through the spinal cord
- dorsal, ventral, lateral columns
there are ascending and descending tracts of myelinated axons that run the length of the spinal cord
What horns are in the inner gray matter of the spinal cord?
posterior - sensory neurons
anterior - motor neurons
lateral - autonomic nervous system
highly organised based on nerve function
gray and white commissures
axons that cross from one side of the spinal cord to the other
central canal
centre of gray commisure
