یونس کمالی - Department of Basic Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
ذبیح ا... خاکسار - Department of Basic Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.

The only branch that detaches from the aortic arch of adult horses is the common brachiocephalic trunk. This report describes a rare case of the unusual arterial arrangement of the aortic arch in a female adult horse. The aortic arch was found to lack a common brachiocephalic trunk and had instead two branches, the first being a brachiocephalic trunk and the second being a left subclavian artery. The direct origin of the left subclavian artery from the aortic arch is very rare in horses and a similar case has not been reported previously. The potential embryologic and phylogenetic aspects of this variation are discussed.

Common brachiocephalic trunk, horse, left subclavian artery