Full Heart (Posterior View) Description [Continued from above] .
. . pulmonary arteries and veins, and the vena cava. The
inferior tip of the heart, known as the apex, rests just
superior to the diaphragm. The base of the heart is located
along the body’s midline with the apex pointing toward the left
side. Because the heart points to the left, about 2/3 of the
heart’s mass is found on the left side of the body and the other
1/3 is on the right. Anatomy of the Heart The heart sits within
a fluid-filled cavity called the pericardial cavity. The walls
and lining of the pericardial cavity are a special membrane
known as the pericardium. Pericardium is a type of serous
membrane that produces serous fluid to lubricate the heart and
prevent friction between the ever beating heart and its
surrounding organs. Besides lubrication, the pericardium serves
to hold the heart in position and maintain a hollow space for
the heart to expand into when it is full. The pericardium has 2
layers—a visceral layer that covers the o