Evolutionary analysis of morphology and irrigation of the thymus of boar’s (Sus scrofa Linnaeus, 1758)

ABSTRACT The objective of this study was to comparatively describe the arteries responsible for the irrigation of the cervical and thoracic thymus lobes of Boars, also determining the morphological characteristics of this body in this species to the point of evolutionarily correlating them with other representatives of the Suidae family. The left and right cervical thymic lobes received branches distributed by common right and left, superficial right and left carotid arteries, and neck and, sometimes, the outer left chest and left subclavian arteries. This feature was vascular maintained throughout evolution and is present in more recent strains and breeds of swine. Irrigation of the right and left thoracic thymic lobes was performed predominantly by direct and indirect ipsilateral and contralateral branches of the right and left internal thoracic arteries and also by branches of the left subclavian artery. Direct branches of the right and left superficial cervical artery and right branches of the right internal thoracic artery were found for the average thymic lobe, this being a unique description in this species, demonstrating a primitive feature in this evolutionary ancestor.