Spinal Cord and Meninges Flashcards
What is the CNS comprised of?
brain
spinal cord
What part of the CNS connects the brain and spinal cord?
brain stem
What makes up the brain stem?
medulla oblangata
pons
What covers the brain, spinal cord, and brain stem and contains CSF?
meninges
What is contained in the meninges?
CSF
Are afferent structures sensory/motor?
sensory
Are efferent structures sensory/motor?
motor
What are the different structures within the sensory/afferent spinal cord/nerves?
dorsal horn
dorsal root ganglia
ascending corticospinal pathways
axons from body traveling to dorsal root and dorsal horn
What are the different structures within the motor/efferent spinal cord/nerves?
ventral horn
lateral horn
descending corticospinal pathways
axons from ventral and lateral horn traveling out to body
Do the dorsal and ventral horn contains gray or white matter?
gray
What makes up the gray matter in the dorsal and ventral horns?
cell bodies
unmeylinated
Do the ascending and descending corticospinal pathways contain gray or white matter?
white
What makes up the white matter in the ascending and descending corticospinal pathways?
myelinated axons
Where do axons travel from and to in afferent structures?
from body to dorsal root and dorsal horn
Where do axons travel from and to in efferent structures?
from ventral and lateral horn to body
Which roots are in the spinal cord?
mix of dorsal and ventral
Is the intervertebral disk ventral or dorsal?
ventral
number of nerves in the cervical vertebra
8 (C1-C8)
number of nerves in the thoracic vertebra
12 (T1-T12)
number of nerves in the lumbar vertebra
5 (L1-L5)
number of nerves in the sacral vertebra
5 (S1-S4)
5th sacral and coccygeal nerves pass through the sacral hiatus
What protects the spinal cord?
vertebrae
ligaments (hold vertebrae together)
muscles (stabilize)
CSF
How do the meninges protect the spinal cord
absorb shock
How many segments/pairs of spinal nerves?
31 pairs
outermost meningeal layer
dura mater
middle meningeal layer
arachnoid mater
innermost meningeal layer
pia mater
Where is CSF found?
subarachnoid space
Purpose of the denticulate ligament
anchor SC to dura mater - keeps it in place
what is the toughest meningeal layer?
dura mater
paired extensions of pia mater that attach to the arachnoid and dura mater
denticulate (tooth-like)
What do the denticulate ligaments anchor?
spinal cord laterally in the dural sac
Where are the denticulate ligaments as they leave the dural sac?
run between the ventral and dorsal rootlets of SC
contents of epidural space
extradural adipose tissue (fat)
internal vertebral venous plexus (Batson’s plexus)
contents of subdural space
- potential space between dura and arachnoid mater
- may be opened due to trauma/disease (subdural hematoma)
contents of subarachnoid space
spinal veins and arteries
CSF
arachnoid trabeculae
located from C5-T1
gives rise to cervical plexus and brachial plexus
cervical enlargement
What are the cervical and brachial plexus?
groupings of cervical and thoracic spinal nerves
located in L1-S2
gives rise to lumbar plexus and sacral plexus
lumbar enlargement
What are the lumbar plexus and sacral plexus?
groupings of lumbar and sacral spinal nerves
what are the 5 major anatomical features of the SC?
conus medullaris filum terminale internum filum terminale externum lumbar cistern cauda equina
terminal end of the SC (L1-L2 level)
conus medullaris
pia mater extending from tip of conus medullaris to end of dural sac
filum terminale internum
all dural layers fused together
anchors dural sac in sacrum; extradural
filum teminale externum
enlargement of subarachnoid space from L2-S2
lumbar cistern
L2-S5 and Co spinal nerve roots that form structure that looks like a horse tail in the lumbar cistern
cauda equina
What causes the formation of cauda equina?
differential growth of spinal cord and vertebral column
where can the conus medullaris be located?
anywhere in T12-L3
rare but serious disorder in which the spinal nerve roots that comprise the _____ ___ become compressed and cause a characteristic pattern of neuromuscular and urogenital symptoms (gradual onset)
cauda equina
Segmented spinal arteries arise from: (3)
subclavian artery
descending aorta
internal iliac artery
What are the 3 arteries that arise from the subclavian artery?
vertebral artery
ascending cervical artery
deep cervical artery
What are the 2 arteries that arise from the descending aorta?
posterior intercostal artery
lumbar artery
What artery arises from the internal iliac artery?
lateral sacral artery
The segmented spinal arteries contribute to arteries that run longitudinally from the brain stem to the conus medullaris: (2)
anterior spinal artery
paired posterior spinal artery
Which artery does the anterior spinal artery arise from?
vertebral artery
Which artery do the paired posterior spinal arteries arise from?
vertebral artery or cerebellar artery
What happens to the segmented spinal arteries once they enter the intervertebral foramina?
split into anterior (2) and posterior (3) radicular arteries
What the the anterior and posterior radicular arteries supply?
dorsal and ventral roots of the spinal cord
The segmented spinal arteries give off which arteries
that anastomose?
segmental medullary arteries (4)
anterior spinal artery (5)
What is the largest segmental medullary artery?
radicularis magna (artery of Ademkiewicz)
Where does the radicularis magna arise and what does it supply?
lower thoracic or upper lumber region
supplies lower spinal cord including lumbar enlargement
