Isolated Fracture of the First Rib Produced by Muscular Traction1

Isolated unilateral fracture of the first rib due to muscular (scalenus anticus) pull is of infrequent occurrence. A review of the literature reveals about 64 reported cases of isolated fracture of the first rib, unilateral and bilateral, due to all causes. Knoepp (5), in a series of 386 cases of rib fractures of all types, found 32 isolated fractures of the first rib, and only 2 of these were due to muscular pull (0.5 per cent of the total series; 6.0 per cent of the first rib fractures). Breslin (2), reporting 5 of his own cases and reviewing 27 others, found 2 cases due to muscular pull (also 6.0 per cent of first rib fractures). The first rib is the shortest in the thoracic cage. It is flat and broad, having two surfaces, which face cephalad and caudad. On the upper surface near its mid-portion is a bony prominence, the scalenus tubercle, the site of insertion of the scalenus anticus muscle. Kellogg Speed (6) says that “the length of the first two ribs and the clavide usually protect them against frac...