Claw finger.
Besides the known intrinsic paralytic claw hand, the claw hand without intrinsic paralysis is also observed. The mechanisms of clawing of the finger in individuals with intrinsic paralysis are reviewed and are explained by the tensing effect of the flexor tendons and the relaxation of the extensor digitorum communis tendon distal to the transverse lamina as the metacarpophalangeal joint is extended. Early recognition, prevention, and treatment are essential. The clawing of the finger in those without intrinsic paralysis is a result of maintaining a position of flexed wrist, extended metacarpophalangeal joint, and flexed interphalangeal joints; thus an extension contracture of the metacarpophalangeal joint may develop. Experiments show that this contracture blocks not only the action of the extensor digitorum communis tendon, but also the interossei in finger extension. Early proper positioning and exercises may prevent the deformity.
D003286:Contracture / Q000517:prevention & control; D005385:Fingers / Q000033:anatomy & histology / Q000503:physiopathology; D006227:Hand Deformities, Acquired / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D008662:Metacarpophalangeal Joint / Q000033:anatomy & histology; D010243:Paralysis / Q000150:complications; D026741:Physical Therapy Modalities; D011187:Posture; D013710:Tendons / Q000033:anatomy & histology