Summary of nerve injuries

Question 1

Most common sites for prolapsed intervertebral disc

Answer 1

L5/S1

L4/L5

Question 2

Paracentral disc herniation

Answer 2

affects traversing nerve (eg if L4/L5 prolapse, L5 is affected)

Question 3

Where does the sciatic nerve emerge from?

Answer 3

Greater sciatic foramen

Question 4

What is piriformis syndrome?

Answer 4

Compression of sciatic nerve by piriformis muscle

Question 5

Piriformis symptoms

Answer 5

Dull ache in buttock
Typical sciatica pain 
Pain when walking up stairs/inclines
Increased pain after prolonged sitting 
Reduced range of motion of hip

Question 6

Movement effects if sciatic nerve is damaged

Answer 6

Hamstrings paralysed (no knee flexion)

No anterior/posterior/lateral leg supply (no dorsi/plantar flexion, inversion and eversion and no toe movement)

Question 7

What is positive trendelenburg side mean?

Answer 7

Pelvis on contralateral (other side to injury) side drops (sound side sags)

eg if injured left superior gluteal nerve, right pelvis will drop

Question 8

Meralgia Paraesthetica

Answer 8

compression to lateral cutaneous nerve as it pierces inguinal ligament or fascia lata

Question 9

What is positive tinels sign?

Answer 9

Tapping nerve at site of entrapment = tingling/paraethesia (usually in meralgia paraesthetica)