TABLE OF CONTENTS
Horse
- The base is broader and the length from the base to apex is shorter.
- The long axis is more oblique.
- The anterior border is more strongly convex.
- It weighs about 2.9 kg to 3.1 kg.
- The intermediate groove is absent.
- Instead of os cordis, the aortic ring contains on the right side a plate of cartilage.
- Sometimes a small plate of cartialge is present on the left side.
Dog
- It is ovoid in shape. The apex is blunt and rounded.
- The long axis is very oblique. The base faces the thoracic inlet.
- The apex is in close relation to the diaphragm at its sternal part.
- The left (ventral) and right (dorsal) longitudinal grooves meet with each other.
- An intermediate groove is present.
- The weight of the heart of a medium sized dog is 150 to 180 gms. The tricuspid valve has two chief cusps and three or four small ones.
- There are four musculi papillaris in the right ventricle, all of which spring from the septal wall.
- The bicuspid valve consists of two large cusps and four or five small ones.
- There are two musculi papillaris in the left ventricle, both of which arise from the lateral wall.
Fowl
- It is proportionately larger.
- It has the form of an acute cone and lies partly between the two lobes of the liver and partly anterior to them.
- The apex is directed backwards and slightly to the left of the median line.
- There are two anterior vena cavae and a single posterior vena cava.
- A muscular fold called the eustachian valve is found to the right of the opening of the posterior vena cava.
- The right atrio ventricular opening is a curved slit and its valve is a muscular leaf, which has neither cusps nor chordae tendinae.
- Musculi papillaris are absent in the right ventricle. The pulmonary artery opening has three semilunar cusps.
- The left atrium is smaller than the right and the two pulmonary veins open into it by a common opening. The left atrio-ventricular valve is guarded by membranous cusps corresponding to the bicuspid valve of mammals.
- The musculi papillaris and chorda tendinae are present in the left ventricle.
- The aortic opening has the three semilunar cusps.
