Abstract
The anatomy, histology, pathology and clinical features of torsion of the testis and its appendages are described. The original historical descriptions and the literature are reviewed. A series of 10 patients with torsion of the testis and nine patients with torsion of the hydatid of Morgagni is presented in detail. The differential diagnosis is discussed and treatment described. An estimate of the relative frequency of the conditions has been made from the case records of patients admitted to the Royal Children''s Hospital between 1950 and 1960.