Comparative anatomical studies of thyroid and thymic arteries: I. Rat (Rattus norvegicus albinus).
The thyroid and thymic arteries were investigated in 50 male and 50 female rats. In more than 70% of the animals, on both sides the cranial thyroid artery forms a common trunk with the ascending pharyngeal artery. The caudal thyroid artery arises not from the deep cervical but from the pericardiacophrenic artery. It may be replaced, however, by a branch of some other artery, such as the brachiocephalic, subclavian, vertebral, or ascending cervical, suggesting a shift of its origin from the internal thoracic artery to the thyrocervical trunk as in man. All the thoracic lobes of the thymus are supplied directly by a thymic branch of the internal thoracic artery or indirectly by a branch of the pericardiacophrenic artery. More than half of the specimens have a cervical thymic lobe of variable size, which is supplied by a branch of the cranial thyroid, external carotid, and/or occipital arteries. Some of these thymic arteries, except those from the external carotid and occipital arteries, reach the thoracic lobe. The thoracic lobes lacking a cervical lobe may be supplied by the thymic branch arising only from the cranial thyroid artery. Other anomalous arteries supplying the thoracic lobe are derived from the superficial cervical and/or the right common carotid arteries. These results show that the thymic arteries of rats are basically similar to those of man, although they display a clear difference in their frequency and origin.
Yamasaki
M
M
Department of Anatomy, Akita University School of Medicine, Japan.
D000818:Animals; D001158:Arteries / Q000033:anatomy & histology*; D005260:Female; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013950:Thymus Gland / Q000033:anatomy & histology / Q000098:blood supply*; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000098:blood supply*