Nerves 2: Forearm, Hand, Leg and Foot

Question 1

Where is injury of the median nerve common?

Answer 1

cubital fossa:

• elbow dislocation
• supracondylar fracture of humerus

Question 2

What is the result of injury to the median nerve?

Answer 2

loss of flexion of thumb, index and middle finger - these digits cannot be made into fist

Question 3

What does injury to ant. interosseous nerve cause?

Answer 3

loss of flexion of distal interphalangeal joints of thumb, index and middle finger

Question 4

what nerve may be at risk in venous access or varicose vein surgery?

Answer 4

saphenous nerve

Question 5

which nerve may be harvested for nerve grafting?

Answer 5

sural

Question 6

where is sensory distribution for the saphenous nerve?

Answer 6

• medial leg

- proximal border of medial foot

Question 7

where is sensory distribution for sural nerve?

Answer 7

• lateral and posterior leg

- proximal border of lateral foot

Question 8

where is sensory distribution for tibial nerve?

Answer 8

heel

Question 9

where is sensory distribution for medial and lateral plantar branches of tibial nerve?

Answer 9

sole of foot and digits

Question 10

where is sensory distribution for deep fibular nerve?

Answer 10

• 1st cleft, dorsally

Question 11

where is sensory distribution for superficial fibular?

Answer 11

most of dorsum (not nail beds)

Question 12

what injury is most common in damaging the radial nerve?

Answer 12

mid shaft fracture of humerus

Question 13

what is a mid shaft fracture of humerus?

Answer 13

• “wrist drop”

- difficulty gripping a cup/mug

Question 14

where does the median nerve pass between?

Answer 14

2 heads of pronator teres

Question 15

what nerve passes through the carpal tunnel?

Answer 15

median nerve along with:

- 9 tendons (FDS, FDP, FPL)

Question 16

what happens if the median nerve is compressed in carpal tunnel?

Answer 16

thumb opposition may be lost - affecting fine grip

Question 17

what may give symptoms similar to carpal tunnel syndrome?

Answer 17

anterior dislocation of lunate - may compress median nerve

Question 18

what does injury to the ulnar nerve at the medial epicondyle of humerus cause?

Answer 18

SENSORY LOSS:

• both palmar and dorsal surfaces
• medial hand
• medial 1.5 digits

Question 19

what does loss of flexor carpi ulnaris do?

Answer 19

makes it difficult to adduct the wrist, and there is radial deviation on wrist flexion

Question 20

what does loss of flexor digitorum to ring and little fingers do?

Answer 20

• their distal interphalangeal joints cannot be flexed

- flexion is weakened in those medial fingers (difficult to make a fist)

Question 21

what is a positive Froment’s sign?

Answer 21

• test by asking patient to clasp a sheet of paper between thumb and palm (adduction)
• uses thumb abduction (radial nerve)
• uses flexion of distal interphalangeal joint (median nerve)

Question 22

how are the interossei tested?

Answer 22

DAB - dorsal abduct

PAD - palmar adduct

Question 23

what is the result of weakened/wasted thenar muscles?

Answer 23

• metacarpophalangeal extension
• interphalangeal flexion
• hand looks like a claw
• claw is restricted to ring and little fingers

*claw is less pronounced if nerve injury is at elbow as the flexing effect of flexor digitorum profundus is lost (ulnar paradox)

Question 24

what nerve supplies the anterior compartment of the leg?

Answer 24

deep fibular nerve

Question 25

what nerve supplies the lateral compartment of the leg?

Answer 25

superficial fibula

Question 26

what nerve supplies the posterior compartment of the leg?

Answer 26

tibial nerve

Question 27

how might injury to the common fibular nerve occur?

Answer 27

• most common: at head/neck of fibula by fracture
• nerve is subcutaneous, susceptible to direct trauma
• compression by plaster cast that is too tight

Question 28

what results from a common fibular nerve injury?

Answer 28

• loss of ankle and digit dorsiflexors and evertors
• causes footdrop (plantar flexion and inversion)
• loss of sensation of lateral leg and dorsum of foot

Question 29

why is injury to tibial nerve rare?

Answer 29

due to its deep position

Question 30

what results from tibial nerve injury?

Answer 30

• loss of ankle and digit plantarflexion

- loss of sensation to sole

Question 31

what is the result of medial plantar compression?

Answer 31

along medial aspect of sole:

• aching
• numbness or tingling (paraesthesia)

Question 32

injury to what nerve in the foot may cause a claw deformity?

Answer 32

ulnar nerve