DOES AN ULNAR NERVE LESION INFLUENCE THE MOTION OF THE INDEX FINGER

Clawing of the ring and little fingers and ''rolling'' during prehensi on grip are well-known clinical phenomena of ulnar nerve lesions. In c ontrast to this the index and middle fingers seem to move normally. We compared the movement of right index fingers in healthy people with t he right index fingers of people with an ulnar nerve lesion. The movem ent was measured using a three-dimensional real time motion analysis s ystem based on ultrasound. The angles of the joints were plotted in a rectangular coordinate system. Statistical analysis of the numerical d ata showed no difference between the two groups. We trained a neural-n etwork (Learning Vector Quantization) with the data of both groups. Th e network was able to distinguish between people with and without lesi ons of the ulnar nerve. We conclude that prehension grip of the index finger is also influenced by paralysis of the ulnar nerve.