Investigation of Human Fetal Thymus Blood Supply

Abstract

The fetus in utero is in a sterile environment, protected from contact with most microorganisms. The thymus plays a crucial role in the maturation of T-lymphocytes, as the generation of immunocompetent T-cells requires an in trathymic differentiation of precursor cells. Thymic pathological processes are sometimes healed only by its extirpation, so knowledge of thymus vascularisation is of great importance. The aim of this study was to investigate anatomic variations of human fetal and newborn's thymus vascularisation. The research comprised 20 newborns who died due to intracranial hemorrhage, 3-20 days after birth. Contrast (gelatin ink) injected into the abdominal aorta filled thymic arteries retrogradely. Lateral branches of the inferior thyroid artery were found to provide arterial blood to the thymus cervical part in 11 cases, while in the other nine, branches of inter nal thoracic arteries were found. After investigating the thoracic part of the thymus gland we found that the internal thoracic artery supplied ipsilateral lobes in 16 newborn, while in one case, the left one was found to have branches for both lobes. The thoracic part of the thymus had arterial vascularisation from pericardial ves sels in two cases while in one the presence of an odd interlobal artery originating from brachiocephalic trunk was observed. Knowledge of anatomic variations of thymus arterial vascularisation is of great importance in invasive diagnostic proce dures as well as in surgical intervention. (Thai J Obstet Gynaecol 1991;3: 7-11.)