A macroanatomic investigation on the arterial vessels of the canine thymus

Thymus is a lymphoid organ which has endocrine function [3]. It also plays a very important role in the immune system [1]. The organ is situated in the ventral part of the cranial mediastinum, between the first and sixth intercostal space, on the sternum [4, 11]. The organ consists of two yellowish lobes, one is named right lobe, the other left lobe. [3, 8, 11, 17]. In the newborn animals it is well developed [3, 11, 13, 14, 17]. Prior to the prepubertial period and lacteal dentition, thymus is completely developed. Then, involution process begins [3]. In the first 3-6 months of the life it gradually develops. In 6-12 months aged dogs, thymic involution appears at different stages [17].