Blood supply to the cranial venae cavae and the heart in the laboratory shrew (Suncus murinus).

The blood supply to the cranial venae cavae on both sides and to the heart was studied macroscopically in 40 adult laboratory shrews (Suncus murinus) of both sexes injected either with Neoprene latex into the abdominal aorta (25 animals) or with Mercox into the left ventricle (15 animals). The 1st branch of the left subclavian artery in 23 animals of the 1st group ramified caudal to the aortic arch and descended between the aorta and the trachea to supply mainly the large left cranial vena cava that lay on the dorsal surface of the left atrium, while a branch that arose between the 1st and 2nd intercostal arteries on the right in 25 animals supplied the right cranial vena cava caudally after giving rise to a branch to the oesophagus. In 2 animals the artery to the left vena cava arose directly from the thoracic aorta at the level of the 4th intercostal artery and then followed the course described above. From these considerations, these vessels in the laboratory shrew would correspond to the accessory coronary arteries of Halpern (1957) in the rat. In the 15 animals of the 2nd group, the left coronary artery was distributed to the atrium and the ventricle on left side and to the upper half of the interventricular septum, the artery on the right supplied the atrium and the ventricle on right side, the interatrial septum and lower half of the interventricular septum.