Shape and Orientation:

• The heart has a somewhat pyramidal or conical shape.

• Its base is directed upwards towards the right shoulder and is broad.

• The apex is pointed downwards and towards the left hip.

Surfaces and Margins:

• The external surface of the heart can be divided into five smaller surfaces.

• These surfaces are limited by four margins: the superior margin, the right margin, the inferior margin, and the left margin.

External Sulci:

• The outer surface of the heart contains grooves known as external sulci.

• These sulci are created by internal partitions of the heart.

• Coronary vessels, which provide arterial blood supply and venous drainage to the heart, pass within these external grooves.

Great Vessels:

• The heart is connected to several larger blood vessels that either arise from it or return to it.

• These vessels are responsible for distributing blood throughout the body.

• Due to their significant diameter, they are termed the great vessels of the heart.

Pericardium:

• The heart and the roots of the great vessels are enveloped by a serous sac called the pericardium or pericardial sac.

• The pericardium provides protection and anchorage for the heart while allowing smooth movement during contractions.

• It consists of an outer fibrous layer and an inner serous layer.