Peripheral Nervous System Tutorial - Case 2

Question 1

This man has sciatica. He describes the pain as stabbing, burning or shooting and has pins and needles in his right leg. He says that he feels as though his right leg is weaker than the left. Which nerve roots are affected?

Answer 1

Look at the dermatome map Dorsal and ventral nerve roots are affected because motor function is weakened but don’t forget that at least 2 nerves innervate each muscle so it’s unlikely that he would completely lose motor function L5 and S1

Question 2

what is sciatica also known as?

Answer 2

lumbar spinal radiculopathy

Question 3

how can lumbar spinal radiculopathy arise?

Answer 3

compression of the spinal nerves, caused by:

• slipped (herniated) spinal disc
• narrowing of the intervertebral foramina where the nerves emerge (foraminal stenosis)
• slippage of the vertebrae with respect to one another (spondylolisthesis).
• Other non-disc causes include malignancy (e.g. metastatic bone disease), arthritis, bone growths, piriformis syndrome (where the nerves are compressed by the contraction of the piriformis muscle in the buttocks).

Question 4

How can lumbar spinal radiculopathy be treated?

Answer 4

• nonsteroidal anti-inflammatory drugs (NSAIDs) eg. ibuprofen
• Exercise, stretching
• Epidural injections - can be delivered into the caudal part of the spine (sacral hiatus), rather than the site commonly used for e.g. pain relief during childbirth (L3/L4 space).
• Decompression surgery/discectomy. These don’t always provide full pain relief!

Question 5

Which physical test can be used to confirm a diagnosis of sciatica?

Answer 5

straight leg raise test

Question 6

where is the epidural space located?

What does it contain?

Answer 6

Between the dura mater and the periosteum of the vertebrae.

It contains fat and small blood vessels