In order to ensure the efficacy of several types of grips, the first web space and the function of contra-opposition, i.e. spread of the thumb from the rest of the hand, must be normal. The anatomic elements that contribute to this function are as follows: the trapezometacarpal joint, the range of motion which may be limited if cartilage lesions, osteophytosis or ligament contractures are present; the first dorsal interosseous, the adductor pollicis muscles and the fascial clefts between them. Contracture of these fasciae, usually ischemic in nature, may cause contracture of the first web space ; the neurovascular elements, which are implicated in paralysis and Volkmann's contracture ; the teguments of the web space and thenar aponeurotic system in which cord-like thickening (as in Dupuytren's contracture), accidental or surgical incisions, may result in severe contracture of the first web space. Involvement of these anatomic structures may be isolated or, more often, associated. Surgery must be adapted to each case, which means taking painstaking care in the evaluation of these factors by thorough clinical examination, and completed by adequate radiograms.