LESI LESI Anatomy and Neuroanatomy

Question 1

The epidural space in the lumbar region is located between which two structures?

Accepted Answer

The dura mater and the ligamentum flavum

Answer

The lumbar epidural space lies between the dura mater anteriorly and the ligamentum flavum posteriorly.

Question 2

Which lumbar interspace is most commonly used for a caudal epidural steroid injection approach?

Accepted Answer

Sacral hiatus (S4-S5 level)

Answer

Caudal epidural injections are performed through the sacral hiatus, which is the caudal opening of the sacral canal.

Question 3

The conus medullaris typically terminates at which vertebral level in adults?

Accepted Answer

L1-L2

Answer

In adults, the spinal cord (conus medullaris) generally ends at the L1-L2 level, making injections below this level safer.

Question 4

Which nerve roots form the sciatic nerve that is commonly implicated in radicular pain treated by LESI?

Accepted Answer

L4-S3

Answer

The sciatic nerve is formed by nerve roots L4 through S3, which are frequently involved in lumbar radiculopathy.

Question 5

The ligamentum flavum, which is traversed during interlaminar LESI, is composed primarily of which tissue?

Accepted Answer

Yellow elastic fibers

Answer

The ligamentum flavum ('yellow ligament') is composed predominantly of yellow elastic fibers, giving it its characteristic color and elasticity.

LESI - Lumbar Epidural Steroid Injection Practice Test