The length and termination of the circumflex branch of the left coronary artery were studied in 81 hearts, after injection of the coloured substance containing a radiopaque medium. The hearts were radiographed, dissected, drawn and photographed. The short type of circumflex branch, defined as a branch that did not reach the crux cordis, was found to be much more frequent (86.4%) than the long type and terminated in the majority of the cases (76.5%) as one of the posterior branches of the left ventricle.