In order to determine the relationship between myocardial bridging and sudden death, the authors analysed retrospectively the macroscopic and histological features of 19 cases of myocardial bridging of the left anterior descending artery (LAD) out of a series of 930 medicolegal autopsy studies. The patients (15 men and 4 women) had an average age of 39.2 years. A potentially lethal cardiac abnormality was found in addition to the myocardial bridge (ischaemic, cardiomyopathy, conduction tissue lesion) in 11 cases; in the other 8 cases, 7 had minor abnormalities and 1 heart was absolutely normal (a 47 year old woman who died while swimming but not of drowning). All hears had fresh, microscopic, ischaemic lesions in the territory of the LAD artery, demonstrated by LIE staining (basic fuschin). The anatomical lesions of the coronary arteries at the site of bridging were varied: 11 dense collagen fibrosis of the adventicia, 16 intimal fibroses of varying degrees of thickness (10 circumferential), 2 atherosclerotic plaques (a 40 and a 54 year old man), 2 recent thromboses (1 at the site of the bridge in a 50 year old man, and the other just distal to the bridge in a 25 year old man). In only 1 case (39 year old woman) there were no microscopic changes of the LAD artery at the site of the myocardial bridge. The hypothesis of the responsibility of the myocardial bridge in the occurrence of sudden death, either during an acceleration of the cardiac rhythm (milking effect) or by thrombotic or spastic phenomena, cannot therefore be excluded.