Upper Limb Nerves Lesions: Examinations; median, radial, ulnar nerve specific

Upper Limb Nerves Lesions: Examinations (by Dr.J Archer, notes of sheer gold)

1. Complete the normal peripheral nervous system expiation of the upper limb
2.What nerves do this test? -- Median Ulnar radial
3.How do you know which one is being tested?

Ulnar Nerve: C8-T1

Remember the route that this nerve follows - Here are some good tricks to remember:

1. Remember the dermatomal pattern of sensory loss for the ulnar nerve.
2. Flexor digitorum profundus (FDP) C8 - flexes the DIP of the ring and little finger
3. Lumbricals C8 - flexes the PIP of the ring and little finger
4. Interossei (PAD - Palmar interossoi adduct - hold this between your fingers, DAB - doral interossoi abduct - push out against my finger)

Ulnar nerve lesion signs:
- general wasting (dorsal guttering, hollowing of the web space) - thenar eminence sparing
- LOW LESIONS - Will result in a CLAW HAND : the MCP of the ring and little finger are hyperextended and the IP are flexed, (FDP intact). Weakness of abduction and adduction of the fingers and thumb. Sensory loss over the medial side of the hand and little finger + medial border of the ring finger. (Use Froments sign - paper between thumb and finger- testing adductor pollicis of thumb against finger). Low lesions occur at the wrist.

- HIGH LESIONS - FDPs are also paralysed and so the DIPs are not flexed and the clawing is less obvious.Called the ULNAR PARADOX. High lesions occur at the elbow - OA and RA.

Median Nerve : C6-T1

Remember the route that this nerve follows -

Good tricks to remember (LOAF muscles)

1. Lateral two lumbricals (flexes at the PIP of index and middle)
2. Oppenens pollicis - thumb to little finger
3. Abductor pollicis brevis - palms up, lift thumb toward the ceiling
4. Flexor pollicis brevis - touch your palms with your thumb
5. Think about the pattern of sensory loss
6. Lastly, another imp muscle: median part of FDP of index and middle fingers - flexes at the DIP....

Median nerve lesions- eg carpal tunnel syndrome

- Thenar wasting
- Weaknes of LOAF muscles
- Reduced sensation over the palmar side of the hand to lateral side of ring finger
- percussion over the wrist produces tingling (Tinel's sign)
- flexing the wrist causes tingling (phalen's sign) - for one minute

Causes - CTS (idiopathic most common, then RA, pregnanct, OA), in addition to wrist lacerations, foream fracture #, elbow #

Radial Nerve : C6-8

Signs:

- wrist drop, confirm intrinsic muscles of the hand intact - (therefore not an ulnar or median nerve palsy) - by lying hand on a pillow, unable to straighten fingers; (because the action of the radial nerve is to extend those fingers and extend at the wrist)
-Sensory loss over the first dorsal interosseous
- high or low lesion - test the triceps reflex (C7) - if present lesion is below the spiral groove of humerous. If it is absent, it implies the lesion, is high, up in the axilla -[ saturday night palsy.]

Median & ulnar nerve TIPS: things to help u remember - :
Remember just two muscles - Abductor Poll Brevis(median) and 1st Dorsal Interossei (ulnar)

Remember that if they cannot lift their thumb - but can push 1st finger our against your hands (holding back the other three) = median nerve problem
If they are able to lift thumb, but first finger test is weak = ulnar lesion/problem.

And finally if there are no problems with thumb or finger test - consider radial problem.