Spinal Cord and the Meninges Flashcards
boundaries of the vertebral canal
Lateral: intervertebral foramen
Anterior: vertebral body, intervertebral disc
AF = annulus fibrosus
NP = Nucleus pulposus
Posterior: spinous process
medial: suprasponous ligament and intraspinous ligament
Where does the spinal cord begin and end
begins at the foramen magnum of the skull as a continuation of the medulla oblongata
Ends at L1/L2 (inferior end is conus medullaris which narrows as film terminal
Where are the enlargements located
cervical = C4 - T1 (brachial plexus)
lumbosacral = T11 - S1
(lumbosacral plexus)
What is the caudal equina
roots of lumber, and lower, spinal nerves
dura mater
outermost, thick protective layer
it is called the dural sac and is not attached to bone
narrows at border of C2 vertebrae where it fuses with film terminale
arachnoid mater
avascular layer lying deep tot eh dura no space between these layers
connects to Pia via arachnoid trabeculae
where does the subarachnoid space
ends at lower border of S2 vertebra
also encloses the caudal equina
pia mater
thin vascular layer that also covers spinal roots
becomes the film terminale
in the vertebral canal, triangular extensions of Pia (denticulate ligaments) are laterally attached to the arachnoid mater in the dural sac and suspend spinal cord
epidural space
fatty matrix
runs from foramen magnum to sacral hiatus
internal to periosteum
contains internal vertebral venous plexus
3 longitudinal arteries:
- branches of the subclavian artery
- lie on surface of the cord
Numerous segmental arteries:
- branches of the aorta
- enter vertebral canal via intervertebral foramen
vertebral arteries ascend in the neck within
the foramina transversaria of cervical vertebrae and branch after the foramen magnum
two types of longitudinal supply
2 posterior spinal arteries:
- arise from vertebral and posterior inferior cerebellar arteries
1 Anterior:
- arises from vertebral arteries
segmental supply
cervical (arise from vertebral arteries)
thoracic (Arise from intercostal arteries)
Lumbar (arises from lumber arteries)
venous drainage
NO VALVES blood flows slowly in either direction
INTERNAL: lies in extradural fat of epidural space
EXTERNAL: drains medullary cavity of the vertebral bodies and connects segmental veins
