For one to properly embalm the human body, it is necessary to understand the way the fluid will circulate through the body, and the only way we can do this is to study the circulation of the blood as it would occur in life.
To facilitate the description of the blood vascular system, it has been divided into six subdivisions as follows:
(1) Systemic. (2) Pulmonary. (3) Coronary. (4) Portal. (5) Foetal. (6) Collateral.
=The Systemic Circulation.=—The systemic circulation is called the greater circulation of the body. The course of the blood is from the left ventricle of the heart through the aortic semi-lunar valve to the great aorta and its branches which end in capillaries in the tissues of the body then through the veins the terminal trunks of which end in the right auricle of the heart. So the systemic circulation is the circulation of the blood from the left ventricle of the heart to the right auricle of the heart and this circulation has the important function of carrying oxygen to the tissues to nourish them, and of carrying carbonic acid gas back to the heart which is a waste product of the tissues.
The systemic circulation is divided for the sake of convenience into the following:
(1) The arterial system. (2) Capillary. (3) The venous system.
=The Arterial System.=—The blood leaving the heart passes from the left ventricle through the aortic semi-lunar valve, into the ascending aorta. Here the two coronary arteries come off which go to supply the muscular tissues of the heart. The ascending aorta passes into the arch of the aorta. Here are given off the innominate artery to the right and the common carotid and the subclavian to the left. The innominate is only about an inch or two in length, and divides into the right common carotid and the right subclavian arteries. On each side the subclavian passes down beneath the clavical bone and enters the axillary space where it is known as the axillary artery. After leaving the axillary space, the artery passes down the arm and is known as the brachial artery. About one inch below the bend of the elbow the artery divides into two branches, known as the radial and ulnar. The radial goes to the thumb side of the hand, and the ulnar to the little finger side of the hand. The ulnar artery and a branch of the radial form the palmar arch, which gives off the branches to the fingers. Coming off the brachial are the deep brachial arteries and the anastomotica magna arteries which anastomose and give collateral circulation to the forearm, by means of the recurrent radial and ulnar arteries.