The arterial blood supply of the sinu-atrial node in Merino sheep

Abstract

The arterial blood supply to the sinus node district has been studied, by dissections (64) and clearing technique after injection of opaque solution (11), in the heart of 75 sheep. The AA found that this district is vascularized exclusively by the ramus proximalis atrii dextri and ramus intermedius atrii dextri, branches of the right coronary artery, in 57.3% ± 5.7 of the cases. In 33.3% ± 5.4 of the sheep the sinus node area is prevalently supplied by the ramus proximalis atrii sinistri, originating from the left coronary artery, and partially by the ramus intermedius atrii dextri. In 5.3% ± 2.5 of the subjects examined the vascularization of the sinus node district is provided simultaneously by the ramus proximalis atrii dextri, ramus proximalis atrii sinistri andramus intermedius atrii dextri; in the remaining 4.0% ± 2.2 the contribution of the ramus proximalis atrii sinistri is doubtful.