When we describe the heart in this chapter, and in subsequent chapters, our account will be based on the organ as viewed in its anatomical position. Where appropriate, the heart will be illustrated as it would be viewed by the surgeon during an operative procedure, irrespective of whether the pictures are taken in the operating room, or are photographs of autopsied hearts. When we show an illustration in non-surgical orientation, this will be clearly stated.

In the normal individual, the heart lies in the mediastinum, with two-thirds of its bulk to the left of the midline (Figure 1.1). The surgeon can approach the heart, and the great vessels, either laterally through the thoracic cavity, or directly through the mediastinum anteriorly. To make such approaches safely, knowledge is required of the salient anatomical features of the chest wall, and of the vessels and the nerves that course through the mediastinum (Figure 1.2). The approach used most frequently is a complete median sternotomy, although increasingly the trend is to use more limited incisions. The incision in the soft tissues is made in the midline between the suprasternal notch and the xiphoid process. Inferiorly, the white line, or linea alba, is incised between the two rectus sheaths, taking care to avoid entry to the peritoneal cavity, or damage to an enlarged liver, if present. Reflection of the origin of the rectus muscles in this area reveals the xiphoid process, which is incised to provide inferior access to the anterior mediastinum. Superiorly, a vertical incision is made between the sternal insertions of the sternocleidomastoid muscles. This exposes the relatively bloodless midline raphe between the right and left sternohyoid and sternothyroid muscles. An incision through this raphe gives access to the superior aspect of the anterior mediastinum. The anterior mediastinum immediately behind the sternum is devoid of vital structures, so that the superior and inferior incisions into the mediastinum can safely be joined by blunt dissection in the retrosternal space.