A detailed understanding of the arterial anatomy of the shoulder and potential anatomical variations is paramount to building a successful radial catheterization experience. In the majority of patients, the shoulder anatomy is straightforward whether approaching the ascending aorta from the right radial artery or left radial artery. However, there are important variations, including severe subclavian tortuosity and anomalies of great vessel orientation that can significantly increase the difficulty in accessing the ascending aorta and engaging the coronary arteries.
Normal Arterial Anatomy
Details of radial artery anatomy and variations are discussed in a separate chapter. The radial and ulnar arteries arise from the brachial artery, which is a medium-sized vessel (3-6 mm). As it courses centrally, it continues into the axillary artery into the subclavian artery. On the right side, the subclavian artery joins the right common carotid artery to form the innominate artery, which is the most proximal great vessel to arise from the aortic arch. On the left side, the left subclavian artery enters directly into the aortic arch and is the third and most distal of the great vessels to arise from the aortic arch. In normal anatomy, entering the ascending aorta with a guide wire and catheter is generally not difficult whether approaching from the right side or the left side. Once the ascending aorta is accessed with a guide wire, coronary catheters can be advanced and manipulated using standard techniques to engage the coronary arteries.