Traction injury in the internal mammary artery. Report of a case and review of the literature. The internal mammary artery (IMA) is now used routinely along with saphenous vein for myocardial revascularization procedures. We have documented a particular form of non-perforating injury which may reduce blood flow during operation or may lead to early closure of the IMA bypass graft. Traction injury to the intima is well documented in other vessles but has not been previously reported in the IMA. We present a potentially disastrous example of traction injury to the IMA. 