Anatomic variation of the thoracic duct and absence of accessory hemiazygos and hemiazygos veins: case report

Abstract

The thoracic duct is a lymph vessel extending from the abdomen to the base of the neck where it drains to one of the large veins in the region. Many cases are described in the scientific literature, regarding anatomical variations of the thoracic duct, from its origin, path, until its end, and the vast majority intended to relate variations in the last part of the duct. The reports related to variations of its path are very scarce. In a male cadaver dissection in the anatomy laboratory of the Faculdade de Ciências Médicas of Minas Gerais (FCMMG), an anatomical variation of the position of the thoracic duct was found. The thoracic duct was presented to the left of the aorta and spine, from its entry in the aortic hiatus of the diaphragm and chest throughout its length. There were also anatomical variations of interest in the venous circulatory system, such as the absence of the veins: hemiazygos and accessory hemiazygos, and the different location of the azygos vein, which was located to the left of the aorta. These variations have no relation to each other. The study of this variation is important because the knowledge of variations in the thoracic duct path allows lower rates of trauma and iatrogenic lesions in thoracic surgery, with possible serious complications, such as a chylothorax.

Keywords

thoracic duct - hemiazygos - accessory hemiazygos - anatomical variation