Human Anatomy Vol 1

INTRODUCTION

Pericardium, comprising fibrous and serous layers,
encloses the heart pulsating from'womb to tomb'.
Heart is a vital organ, pumping blood to the entire
body. Its pulsations are governed by the brain through
various nerves. Since heartbeat is felt or seen against
the chest wall, it appears to be more active than the
'quiet brain' controlling it. That is why there are so
many songs on the heart and few on the brain. Medi-
tation, yoga and exercise help in regulating the heart
beat through the brain.

Dissection

Make a vertical cut through each side of the pericardium

immediately anterior to the line of the phrenic nerve.

Join the lower ends of these two incisions by a trans-

verse cut approximately 1 cm above the diaphragm.

Turn the flap of pericardium upwards and sideways to

examine the pericardial cavity. See that the turned flap

comprises fibrous and parietal layer of visceral

pericardium. The pericardium enclosing the heart is its

visceral layer (Fig. 18.1a).

Pass a probe from the right side behind the

ascending aorta and pulmonary trunk till it appears on

the left just to the right of left atrium. This probe is in the

transverse sinus of the pericardium.

Lift the apex of the heart upwards. Put a finger behind

the left atrium into a cul-de-sac, bounded to the right

and below by inferior vena cava and above and to left

by lower left pulmonary vein. This is the oblique sinus

of pericardium.

Define the borders, surfaces, grooves, apex and

base of the heart.

-Anonymous

Feolules

The pericardium (Creek around heart) is a fibroserous

sac which encloses the heart and the roots of the great

vessels. It is situated in the middle mediastinum. It

consists of the fibrous pericardium and the serous

pericardium (Figs 18.1b and 18.2).

Fibrous pericardium encloses the heart and fuses

with the vessels which enter,/leave the heart. Heart is

situated within the fibrous and serous pericardial sacs.

As heart develops, it invaginates itself into the serous

sac, without causing any breach in its continuity. The

last part to enter is the region of atria, from where the

visceral pericardium is reflected as the parietal peri-

cardium. Thus parietal layer of serous pericardium gets

adherent to the inner surface of fibrous pericardium,

while the visceral layer of serous pericardium gets

adherent to the outer layer of heirt and formJ its

epicardium.

FIBROUS PERICARDIUM

Fibrous pericardium is a conical sac made up of fibrous

tissue. The parietal layer of serous pericardium is

attached to its deep surface. The following features of

the fibrous pericardium are noteworthy.

1 The apex is blunt and lies at the level of the sternal

angle. It is fused with the roots of the great vessels

and with the pretracheal fascia.

2 The base is broad and inseparably blended with the

central tendon of the diaphragm.

3 Anteriorly, it is connected to the upper and lower

ends of body of the sternum by weak superior and

inferior st ernop ericar dial ligaments (F ig. 1.8.3).

4 Posteriorly, it is related to the principal bronchi, the

oesophagus with the nerve plexus around it and the

descending thoracic aorta.

5 On each side, it is related to the mediastinal pleura,

the mediastinal surface of the lung, the phrenic nerve,

and the pericardiacophrenic vessels.

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