In high lesions of ulnar nerve like elbow fractures or dislocations the degree of clawing is markedly less than in low ulnar lesions this is called ULNAR PARADOX and is due to (AIPG 2011)
|A||The fact that the ulnar half of the FDP is paralysed and hence there is no flexion at the IP joints.|
|B||The lumbricalis are spared and hence there is no clawing|
|C||The Median nerve compensates for the ulnar nerve|
|D||The interossei increase their tone and extend the IP joint.|
The fact that the ulnar half of the FDP is paralysed and hence there is no flexion at the IP joints
a. Claw hand basically is because of paralysis of the lumbricals whose action is flexion at the MCP joint and extension at the IP joints.
b. A claw hand is extended at the MCP and flexed at the IP because of unopposed action of the long flexors, since in the High ulnar lesion the long flexor is paralysed, there is less clawing.