Comparative Anatomy

Question 1

Describe the canine heart

Answer 1

• Ovoid with long axis
• apex lies on sternum at junction of sternum + diaphragm and attachment to latter by the phrenicopericardial pigment
• both right + left AV valves are bicuspid
• heart size may be larger in athletic dogs
• heart disease fairly common

Question 2

Describe the equine heart

Answer 2

• occupies ventral mediastinum to the left of the median plane and further cranial of the diaphragm than the canine
• heart largely covered by forelimb with apex at elbow
• sternopericardial ligament anchors apex to sternum
• horses in training have larger hearts

Question 3

Describe the ruminant heart

Answer 3

• lies 60% to left for midline
• conical with some lateral compression
• relatively small so the long axis is almost vertical and base is horizontal
• apex anchored to sternum by sternopericardial ligament
• caudally heart is relate to diaphragm, behind which lie the reticulum and live
• sharp foreign bodies which are ingested may enter the reticulum then migrate forward to penetrate the diaphragm and pericardium = traumatic pericarditis

Question 4

Describe the porcine heart?

Answer 4

• small in relation to body size
• occupies little more than central half of thoracic space
• covered by forelimb + triceps muscles with long axis at 45 degree to sternum = same in carnivore