Heart Surface Form

In order to show the extent of the heart in relation to the front of the chest, draw a line from the lower binder of the second left costal cartilage, one inch from the sternum, to the upper binder of the third right costal cartilage, half an inch  from the sternum. This represent the base line or upper limit of the organ. Take a point an inch and a half below and three quarters of an inch internal to the left nipple, that is about three and a half inches to the left median line of the body. This represent the apex of the heart.

Draw a line in this apex-point, with a slight convexity downward to this junction of the seventh right costal cartilage to the sternum. This represent to the lower limit of the heart. Joint the line extremity of the first line, that is, the base line with the right extremity of this line, that is, to the seventh right chondro sternal, joint with a slight curve outward, so that it projects about an inch and a half from the middle line of the sternum. Lastly joint the left extremity of the base line and the apex point by a line curved slightly to the left.

The position of the various orifice as follows: The pulmonary orifice is situated in the upper angle formed by the articulation of the third left costal cartilage with the sternum the aortic orifice is a little below and internal to this behind the left border of the sternum, close to the articulation of the third left costal cartilage to this bone. The left auriculo ventricular opening is behind the sternum, rather to the left of the median line, and opposite the fourth costal cartilage. The right auriculo ventricular opening is a little lower, opposite the fourth interspace and in the middle line of the body.

A portion of the area of the heart thus mapped out is uncovered by lung, and therefore gives a dull note on percussion; the reminder, being overlapped by the lung, give a more or less resonant note. The former as known as the area of superficial cardiac dullness is included between a line drawn from the center of the sternum, on a level with the fourth costal cartilage to the apex to the heart and a line drawn from the same point down the lower third of the middle line of the sternum. Below this area merges into the dullness with correspond to the liver.

Surgical Anatomy:
Wound the heart are often immediately fatal, but not necessarily so. They may be non-penetrating, when death may occur from hemorrhage "f" one of the coronary vessel has been wounded, or subsequently from pericarditis; or, on the other hand, the patient may recover. Even a penetrating wound is not necessarily fatal, if the wound is a small one. A flap comprising the whole thickness of the thoracic wall may be made, the cavity of the pericardium opened, and the wound in the heart sutured. This has been done successfully.

Related:

• Pericardium
• Regulation of Heartbeat