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===Position and Shape of the Heart===

===Position and Shape of the Heart===

The heart is located in the thoracic cavity in between the lungs, 60% of it lying to the left of the median plane. The heart’s lateral projection extends from rib 3 to 6. Most of the heart’s surface is covered by the lungs and in juveniles it is bordered cranially by the thymus. Caudally the heart extends as far as the diaphragm. Variations in position and size exist among individuals depending on species, breed, age, fitness and pathology. Roughly speaking, the heart is responsible for about 0.75% of the bodyweight.

The heart is located in the thoracic cavity in between the lungs, 60% of it lying to the left of the median plane. The heart’s lateral projection extends from rib 3 to 6. Most of the heart’s surface is covered by the lungs and in juveniles it is bordered cranially by the [[Thymus - Anatomy & Physiology|thymus]]. Caudally the heart extends as far as the diaphragm. Variations in position and size exist among individuals depending on species, breed, age, fitness and pathology. Roughly speaking, the heart is responsible for about 0.75% of the bodyweight.

The heart is cone-shaped, with a broad base at the top from which the large blood vessels enter and exit. The tip, known as the apex, points downwards and lies close to the sternum. The longitudinal axis of the heart is tilted to varying degrees depending on the species resulting in the base facing craniodorsally and the apex caudoventrally.

The heart is cone-shaped, with a broad base at the top from which the large blood vessels enter and exit. The tip, known as the apex, points downwards and lies close to the sternum. The longitudinal axis of the heart is tilted to varying degrees depending on the species resulting in the base facing craniodorsally and the apex caudoventrally.