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In those animals in which the ventricles of the heart are smooth within and entirely without fibres of muscular bands, or anything like hollow pits, as in almost all the smaller birds, the partridge and the common fowl, serpents, frogs, tortoises, and most fishes, there are no chordae tendineae, nor bundles of fibres, neither are there any tricuspid valves in the ventricles.
The passage leading to the right ventricle lies open, and through it the blood pours till the ventricle is full. Instantly this begins, in its turn, to contract. The tricuspid valve at once closes, and blocks the way backward. The blood is now forced through the open semilunar valves into the pulmonary artery.
The valve between the right auricle and the right ventricle is called the tricuspid valve. It consists of three parts, as its name implies, which are thrown together in closing the opening. Joined to the free edges of this valve are many small, tendinous cords which connect at their lower ends with muscular pillars in the walls of the ventricle.
Moreover, the contraction of the right heart may cause a wave in the veins of the extremities, and he believes that incompetency of the tricuspid valve may be the cause of varicosities in the veins of the extremities. He found the average in persons from 15 to 30 years to be 122 systolic; from 30 to 40, 127 mm., and from the ages of 40 to 50, to be 130 mm.
All the blood flows continuously through both circulations and passes the various parts in the following order: right auricle, tricuspid valve, right ventricle, right semilunar valve, pulmonary artery and its branches, capillaries of the lungs, pulmonary veins, left auricle, mitral valve, left ventricle, left semilunar valve, aorta and its branches, systemic capillaries, the smaller veins, superior and inferior venæ cavæ, and then again into the right auricle.
When the valves are raised and brought together, they form a three-cornered line, such as is left by the bite of a leech; and the more they are forced, the more firmly do they oppose the passage of the blood. The tricuspid valves are placed, like gate-keepers, at the entrance into the ventricles from the venae cavae and pulmonary veins, lest the blood when most forcibly impelled should flow back.
There was a circular lacerated opening in the tricuspid valve, and the ball must have been in the right auricle during the fourteen days in which the man lived.
It is exactly similar in structure and arrangement to the tricuspid valve, except that it is stronger and is composed of two parts instead of three. B. Right semilunar valve. The tricuspid valve and the chordæ tendineæ shown in the ventricle. The right semilunar valve is situated around the opening of the right ventricle into the pulmonary artery.
In all cases of sudden death think of angina pectoris and the rupture of an aneurism. Aortic incompetence. Rupture of heart. Rupture of a valve. Rupture of aortic aneurism. Embolism of coronary artery. Angina pectoris. Cerebral hæmorrhage or embolism. Mitral and tricuspid valvular lesions if the patient exerts himself.
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