Methods and apparatus employed to locate body vessels and occlusions in body vessels finding particular utility in cardiac surgery, particularly minimally invasive cardiac surgery to locate cardiac arteries and occlusions in cardiac arteries are disclosed. An elongated vessel lumen probe incorporating a lumen probe element at or near the elongated vessel lumen probe distal end is advanced into the vessel lumen. A vessel surface probe manipulated by the surgeon and having a surface probe element sensor is employed to detect the lumen probe element and to follow the progress of the vessel lumen probe element as it approaches and is advanced through or is blocked by an occlusion. In the location of a coronary artery, the surface probe element sensor is moved about against the epicardium over the suspected location of the artery of interest until a surface probe element sensor of the present invention at the surface probe distal end interacts with the lumen probe element of the vessel lumen probe.