Lachmans Back Unit II

Question 1

Why are herniations of the nucleus pulposus usually in a posterolateral direction?

Answer 1

Anulus fi brosus is thinner posteriorly than anteriorly

Question 2

What is the vertebral level of the most inferior portion of the spinal cord?

Answer 2

Inferior tip of the spinal cord (the conus medullaris) is at L1/L2

Question 3

What is the inferior limit of the subarachnoid space?

Answer 3

S2

Question 4

What is the cauda equina?

Answer 4

Collection of dorsal and ventral roots from lumbar and sacral levels that extend below the bottom of the spinal cord.

Question 5

The Cauda equina is in the ____ space surrounded by ?

Answer 5

Subarachnoid space surrounded by cerebrospinal fluid.

Question 6

If there is a herniation of the L4/L5 disk, which spinal nerve is most likely to be aff ected?

Answer 6

L5 Spinal Nerve

Question 7

Why is the L5 Nerve susseptible to injury?

Answer 7

The downward slope of the spinal roots forming the lumbosacral nerves, the nerve exiting though the intervertebral foramen below the herniated disk is the one most likely to be compresse

Question 8

What is the optimal site for performing a lumbar puncture?

Answer 8

At L3/L4 interspace or the L4/L5 interspace…

Question 9

Why is L3/L4 interspace or the L4/L5 interspace best for a puncture?

Answer 9

B/c is below the bottom of the spinal cord but above the bottom of the subarachnoid space

Question 10

What landmark is used to identify the proper level for performing a lumbar puncture?

Answer 10

Iliac Crest/s (L4… Then the Sp’s) and the interspaces immediately above and below it are the L3/L4 and the L4/L5 interspace, respectively.

Question 11

Ahorizontal line connecting the highest points of the iliac crests is used to identify

Answer 11

L4

Question 12

What ligaments of the spine must be traversed when inserting a lumbar puncture needle

Answer 12

supraspinous, interspinous, and ligamentum flavum.

Question 13

Why is a lumbar puncture done with the spine in a flexed position
What does it do to the Ligaments ?

Answer 13

Flexing the spine widens the interspinous and interlaminar spaces = more space for needle

Ligaments on stretch, making it easier to penetrate them

Question 14

What is the internal vertebral venous plexus, and what is its significance when performing a lumbar puncture?

Answer 14

Internal vertebral venous plexus is a Venous in the epidural space.

Question 15

What is the internal vertebral venous plexus significance when performing a lumbar puncture?

Answer 15

Needle traverses the epidural space, a vein may be punctured, and blood may enter the needle, giving rise to blood in the cerebrospinal fluid that is withdraw