Spinal Meninges and Spinal Cord Flashcards
three spinal meninges?
dura, arachnoid, and pia mater
function of the spinal meninges
surround, support, and protect spinal cord
also, contain the CSF
dura mater
outermost and strongest layer
location of dura mater?
continuous with dura of cranium
fused with occipital periosteum
how far does dura extend inferiorly?
SV2
how far does dura extend laterally?
along spinal nerves to fuse with neural sheath distal to dorsal root ganglia and with margins of intervertebral foramina
attachment of dura mater?
posterior spinal ligament
-upper cervical and lower lumbar
**provides support
what is dura below SV2?
surrounds filum terminale to form the coccygeal ligament
coccygeal ligament
dura below SV2
-surrounds filum terminale
-attaches inferiorly to periosteum of coccyx
epidural space
area outside dura
-contains fat and blood vessels
**location of internal vertebral venous plexuses
internal vertebral venous plexus?
located in epidural space (outside dura)
subdural space?
area between dura and arachnoid
possible location for subdural hematoma**
arachnoid mater
“spidery mother”
delicate trabeculated layer continuous with cranial arachnoid
extent of arachnoid inferior?
follows limits of dura to SV2
extent of arachnoid laterally?
adheres DIRECTLY to ventral and dorsal roots
becomes continuous with neural sheath at spinal nerve
subarachnoid space
below the arachnoid
**contains CSF
continuous with cranial subarachnoid
pia mater
connective tissue covering spinal cord
*invests blood vessels of the cord and continuous along dorsal and ventral roots to spinal nerve
filum terminale?
formed by the pia mater at the conus medullaris
becomes ensheathed by dura at SV2
denticulate ligaments
lateral pia that forms fibrous bands piercing arachnoid to attach to dura between nerve roots
what anchors the spinal cord?
denticulate ligaments and filum terminale
what is shock absorber for spinal cord?
CSF
length of spinal cord?
45cm
tapers inferiourly to form the conus medullaris
-ends opposite the LV1-LV2 interspace (adults)
pia-glial extensions continue inferiorly to SV2 as filum terminale
spinal cord length through development?
fetus - entire length of spinal column
infant - ends opposite LV3
adult - ends opposite LV1-LV2 interspace
do spinal cord segments coincide with vertebral segments?
no
because of development of the spinal cord
what forms dorsal and ventral roots?
rootlets of a single spinal cord segment
what do dorsal root ganglion contain?
cell bodies of origins (CBO’s) of most of the sensory neurons which einnervate the body below the level of the head
how many pairs of spinal nerves?
31
how many of each type of spinal nerve?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
what happens as you move laterally along rootlets?
when fuse and form spinal nerves
-become invested with all three layers of meninges and fuse with the neural sheath
where do lower lumbar and sacral rootlets leave spinal cord?
conus medullaris forming the cauda equina
cauda equina
from the rootlets past the conus medullaris
conus medularis
tapering end of the spinal cord
what vertebral level is the spinal cord level of lumbar?
T11-12
what vertebral level is spinal cord level of sacral nerves?
LV1
anterior spinal artery?
arises from both vertebral arteries which fuse to form single artery
- courses in the ventral median fissure
- supplies anterior gray and white matter
segmental medullary arteries?
important for the continuity of the anterior spiral artery
posterior spinal artery?
arise as branches of the posterior inferior cerebellar artery (PICA) along the dorsal root joining with opposite counterpart
radicular arteries?
to the dorsal and ventral roots
-receive a segmental blood supply
- radicular arteries that reach the spinal cord are segmental medullary arteries
- not all do
- leaves certain areas of the spinal cord subject to ischemia
segments of spinal cord most vulnerable to ischemia?
T1-4 and L1
possible cause of ischemia to spinal cord?
thoracic or abdominal surgery can lead to ligation of intercostal arteries
