Formation of the external jugular vein in the brown brocket deer (Mazama gouazoubira)

The brown brocket deer (Mazama gouazoubira) is a brown-greyish short-haired wild ruminant living in Central and South Americas. This paper aimed at describing the formation of the external jugular vein in a male specimen which died due to run-over. The facial and cervical regions were dissected so as to allow the visualization of the external jugular vein and its tributaries. This vein was formed by the union of the maxillary and linguofacial veins. The first originated from the superficial and transverse facial temporal veins, and it received along its length the angular vein of the eye, as well as the dorsal and lateral veins of the nose and upper lip. The second was formed after the anastomosis of the lingual and facial veins. The facial vein was originated by the union of the lower lip and deep facial veins, in the middle third of the face, rostral to the masseter muscle. This vascular arrangement differs from that usually observed in domestic ruminants, in which the transverse facial vein is underdeveloped and the facial vein receives the angular vein of the eye, the dorsal and lateral veins of the nose, besides the upper lip vein. The external jugular vein in the brown brocket deer presented the same tributaries than domestic ruminants, however, with a different vessel arrangement of the facial and facial transverse veins.