Vertebral Canal and Spinal Cord

Question 1

change in spinal cord configuration during development

Answer 1

originally spinal cord runs length of spine, eventually bony column grows more rapidly and cord ends at higher levels

some nerve roots must lengthen and course obliquely to intervertebral foramen

Question 2

longest nerve roots

Answer 2

lumbar and sacral/coccygeal roots- travel down via cauda equina

Question 3

conus medullaris

Answer 3

tapered end of cord, at L1-L2

Question 4

filum terminale

Answer 4

extension of medullary cone, vestigal remnant of embryonic tail

internal filum extends from medullary cone to tip of dural sac

external goes from tip of dural sac to sacrum and anchors spinal cord inferiorly

Question 5

2 spinal cord enlargements

Answer 5

cervical- upper limbs

lumbosacral- lower limbs (nerve roots form medullary cone and cauda equina)

Question 6

nerves exit cord..

Answer 6

along inferior aspect of vertebrae (except cervical) but above the disc

Question 7

3 meninges

Answer 7

dura mater
arachnoid mater
pia mater

Question 8

dura mater

Answer 8

tough outer membrane, extends laterally into intervertebral foramina aong roots of nerves, forms dural sleeves

Question 9

arachnoid mater

Answer 9

delicate intermediate inside dura, assoc w/ dural sleeves

Question 10

pia mater

Answer 10

lies on surface of cord

Question 11

subarachnoid space

Answer 11

continuous w/ subarachnoid space around brain, contains CSF

Question 12

denticulate ligaments

Answer 12

lateral extensions of pia mater b/w dorsal and ventral roots, anchor cord laterally

Question 13

epidural space

Answer 13

bw/ vertebral canal and dura mater- contains adipose tissue and internal venous plexous

Question 14

segmental vs longitudinal spinal arteries

Answer 14

longitudinal more important in cervical spinal cord, get smaller as they move down, arise from vertebral arteries

segmental supply the rest, lots of branches laterally exiting IV foramina

Question 15

great anterior segmental artery

Answer 15

aka artery of adamkiewicz, segmental spinal artery

usually arises from lower intercostal, helps w/ circulation of inferior 2/3 of spinal cord

Question 16

venous drainage from spinal cord

Answer 16

anterior and posterior spinal veins then into internal (epidural) venous plexus in vertebral canal

internal plexus connected to external venous plexus via basivertebral veins

Question 17

batsons plexus, clinical significane

Answer 17

network of interconnected vertebral venous plexuses, direct connections also w/ veins in pelvis and posterior thoracic wall

very few valves

path for tumor cells from prostate, breast, and lung to reach vertebrae or cranial cavity

Question 18

ideal spot for spinal tap, ligaments crossed

Answer 18

lower lumbar- L3,4,5 becaus this is below spinal cord and in cauda equina

needle thru spuraspinous, interspinous, ligamentum flavum, dura mater, arachnoid mater, to CSF

Question 19

posterior to anterior layers for spinal tap

Answer 19

skin
supraspinous ligament
interspinous ligament
ligamentum flavum
epidural space
dura mater
arachnoid mater
subarachnoid space- where CSF is

Question 20

support for disc placement

Answer 20

anterior and posterior longitudinal ligament fuse outer portion of IV discs

Question 21

site of deficiency in IV disc location

Answer 21

lateral portion of PLL ligament, slightly weaker

protrusion of nucleus pulposus usually posterolaterally whre annulus is thin and less supported

Question 22

most lumbar disc herniations occur…

Answer 22

L4/L5 or L5/S1

Question 23

rule for affected spinal cord w/ herniated disc

Answer 23

if spinal segment is affected b/w two vertebral segments, the spinal segment is likely the higher one

eg disc herniation b/w L4 and L5 will affect L5 spinal nerve