Primary torsion of omentum: report of six cases.

TORSION of a structure is a turning or twisting about its long axis. Two varieties may be recognized: (1) the unipolar, in which the structure is fixed at one extremity while its distal end swings free in response to any force acting upon it, and (2) the bipolar, in which the structure is fixed at two points with the intervening portion left free to twist axially, in the manner of a hammock. Although Oberst, 1 in 1882, supplemented by Demons, in 1893, presented cases of omental torsion, all their cases were associated with inguinal herniae. According to the literature, Eitel, 2 in 1889, reported the first case of purely abdominal torsion in America as occurring independently of the presence of a hernia. In 1905, Corner and Pinches 3 found among 41 cases reported, 4 independent of hernia. Hederstad, 4 in 1939, reported a review of 40 cases. Mallory, 5 in