[Anatomic variations of the common trunk of the left coronary artery (apropos of 80 dissections)].

An anatomic study of the main left coronary artery is reported : important anatomic variations may occur:--sometimes, the main left coronary artery is missing (1 % of the cases),--its origin may be unusual (from the pulmonary artery),--its average length is 11 mm; but, it may be longer (35 mm) and sometimes very short (less than 8 mm in 15 per cent of the cases) : this last aspect has to be taken in account by the surgeon during aortic valve surgery if a coronary perfusion has been decided.--At last, its division into two branches (anterior descending and left circumflex) is the most usual (65 or 70 per cent of the cases). A third branch of division may exist (diagonal or lateral branch) in about 20 to 30 per cent of the cases. The left coronary artery may also divide into four (or even five) branches in 5 to 10 per cent of the cases.