|Budget Amount *help
¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1992 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1991 : ¥400,000 (Direct Cost : ¥400,000)
The thyroid and thymic arteries were investigated on 60 guinea pigs (GP), 60 rabbits (Rb) 72 house musk shrews (Sun). Results were compaired with those of Polyprotodont marsupials (PM), rats and humans.
The superior thyroid artery was dominant in all species excepting Rb, where the middle thyroid was constant. The human type inferior thyroid artery was rare in other species, but the similar artery arising from the common carotid appeared in rats, GP and Rb. The thyroid ima artery was absent or extremely rare in PM, rats, Rb and Sun. The independent thyroid artery which was not recorded in humans were present in GP, Rb and Sun.
The inferior thymic artery was constant in all species excepting Sun, where the artery was absent in about one half body side and the middle thymic artery supplied the thymus in the remaining instances. The latter artery, however, occurred in high frequency in Rb and humans. The supreme and superior thymic arteries were relatively abundant in rats, Rb and humans and rare or absent in PM and Sun. The middle thymothyroid artery, which was abundant in humans, was rare or absent in other species.
Because the thymus of GP was superficial cervical, its arteries were not comparable to those in other species. However, in GP the thymic artery arising from the lingual and sending a thyroid branch was present. This artery was the highest thymic and thyroid artery observed in all species investigated and seemed that the original or oldest artery supplying both organs.
These results show that the both thyroid and thymic arteries are most complex in humans followed by those in GP, Rb and Sun, and are simplest in PM and rats.