Nerve supplies

Question 1

Hip flexion

Answer 1

Psoas (direct innervation from lumbar plexus)
Femoral nerve (L2-L4) supplies PSOAS

Question 2

Hip extension

Answer 2

Gluteus maximus (inf. gluteal nerve)
Hamstrings (SCIATIC nerve)
Rectus femoris (one of the quads; femoral nerve)

Question 3

Knee flexion

Answer 3

Posterior compartment of thigh i.e. HAMSTRINGS (and adductor magnus)

Question 4

What do the hamstrings do?

Answer 4

Knee flexion and help with hip extension

Question 5

Knee extension

Answer 5

QUADRICEPS (anterior compartment of thigh) - femoral nerve

Question 6

Ankle plantarflexion

Answer 6

Tibial nerve (S1-S2) supplies the posterior calf (tibialis posterior, soleus, gastrocnemius, & the toe flexors)

Question 7

Ankle dorsiflexion

Answer 7

CPN (L4-S2)

Question 8

Wrist flexion, finger flexion (‘make a fist’)

Answer 8

Ulnar nerve –> flexor carpi ulnaris
Ulnar nerve –> medial aspect of flexor digitorum profundus; the MEDIAN nerve does the lateral aspect of FDP so it is a joint effort between (remember by MUFF = median ulnar finger flexion)

Question 9

Thumb ABduction

Answer 9

Median nerve (mainly) --> abductor pollicis brevis
Radial nerve --> abductor pollicis longus

Question 10

Flexion of index and middle fingers at PIPs (palsy of this nerve therefore results in Pope’s hand when trying to make a fist)

Answer 10

Median nerve –> lateral aspect of flexor digitorum profundus (FDP)

Question 11

LOAF muscles are supplied by?

Answer 11

Median nerve:

• Lateral lumbricals (the medial lumbricals i.e. 3rd and 4th fingers = ulnar nerve)
• Opponens pollicis
• Abductor pollicis brevis
• Flexor pollicis brevis

Question 12

Why is there a claw hand in ulnar nerve palsy?

Answer 12

Ulnar supplies the medial two lumbricals, which do PIP extension and MCP flexion, so palsy –> permanent PIP flexion and MCP extension

Question 13

Wrist extension, finger extension, and thumb extension is done by?

Answer 13

Radial nerve –> posterior compartment of forearm (wrist extensors, MCP joint extensors)

Question 14

Elbow flexion and extension?

Answer 14

Radial nerve

Question 15

Finger ABduction?

Answer 15

Ulnar nerve (interossei; these also do finger adduction)

Question 16

In a hand examination, how do you test each nerve?

Answer 16

Ulnar nerve: wrist flexion, finger abduction

Median nerve: thumb abduction

Radial nerve: wrist extension, finger extension, elbow flexion/extension

Question 17

Differentials for weakness of knee flexion and hip extension?

Answer 17

Knee flexion and hip extension is done by the hamstrings (hip extension also by gluteus maximus)- posterior compartment of thigh, supplied by sciatic nerve.

L4, L5, extend my thigh = hip extension
L5, S1, kick my bum = knee flexion

So could be an L4, L5, or S1 radiculopathy; can’ t be sciatic nerve neuropathy as would affect ankle dorsiflexion and plantarflexion too. Can’t be a plexopathy or would affect femoral nerve too - knee extension and hip flexion).

Question 18

Differentials for weakness of dorsiflexion

Answer 18

Unilateral distal LMN weakness:
L4,5- foot points to the sky, so could be a L4/L5 radiculopathy, CES (though would likely be bilateral), plexus compression, CPN neuropathy.

Unilateral UMN weakness:
MND, MS
SOL in brain, stroke (would likely affect whole leg though!)