Nerves 2: Forearm, Hand, Leg and Foot Flashcards
Where is injury of the median nerve common?
cubital fossa:
- elbow dislocation
- supracondylar fracture of humerus
What is the result of injury to the median nerve?
loss of flexion of thumb, index and middle finger - these digits cannot be made into fist
What does injury to ant. interosseous nerve cause?
loss of flexion of distal interphalangeal joints of thumb, index and middle finger
what nerve may be at risk in venous access or varicose vein surgery?
saphenous nerve
which nerve may be harvested for nerve grafting?
sural
where is sensory distribution for the saphenous nerve?
- medial leg
- proximal border of medial foot
where is sensory distribution for sural nerve?
- lateral and posterior leg
- proximal border of lateral foot
where is sensory distribution for tibial nerve?
heel
where is sensory distribution for medial and lateral plantar branches of tibial nerve?
sole of foot and digits
where is sensory distribution for deep fibular nerve?
- 1st cleft, dorsally
where is sensory distribution for superficial fibular?
most of dorsum (not nail beds)
what injury is most common in damaging the radial nerve?
mid shaft fracture of humerus
what is a mid shaft fracture of humerus?
- “wrist drop”
- difficulty gripping a cup/mug
where does the median nerve pass between?
2 heads of pronator teres
what nerve passes through the carpal tunnel?
median nerve along with:
- 9 tendons (FDS, FDP, FPL)
what happens if the median nerve is compressed in carpal tunnel?
thumb opposition may be lost - affecting fine grip
what may give symptoms similar to carpal tunnel syndrome?
anterior dislocation of lunate - may compress median nerve
what does injury to the ulnar nerve at the medial epicondyle of humerus cause?
SENSORY LOSS:
- both palmar and dorsal surfaces
- medial hand
- medial 1.5 digits
what does loss of flexor carpi ulnaris do?
makes it difficult to adduct the wrist, and there is radial deviation on wrist flexion
what does loss of flexor digitorum to ring and little fingers do?
- their distal interphalangeal joints cannot be flexed
- flexion is weakened in those medial fingers (difficult to make a fist)
what is a positive Froment’s sign?
- 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)
how are the interossei tested?
DAB - dorsal abduct
PAD - palmar adduct
what is the result of weakened/wasted thenar muscles?
- 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)
what nerve supplies the anterior compartment of the leg?
deep fibular nerve
what nerve supplies the lateral compartment of the leg?
superficial fibula
what nerve supplies the posterior compartment of the leg?
tibial nerve
how might injury to the common fibular nerve occur?
- most common: at head/neck of fibula by fracture
- nerve is subcutaneous, susceptible to direct trauma
- compression by plaster cast that is too tight
what results from a common fibular nerve injury?
- loss of ankle and digit dorsiflexors and evertors
- causes footdrop (plantar flexion and inversion)
- loss of sensation of lateral leg and dorsum of foot
why is injury to tibial nerve rare?
due to its deep position
what results from tibial nerve injury?
- loss of ankle and digit plantarflexion
- loss of sensation to sole
what is the result of medial plantar compression?
along medial aspect of sole:
- aching
- numbness or tingling (paraesthesia)
injury to what nerve in the foot may cause a claw deformity?
ulnar nerve
