Vena hemizygos is a medical term that refers to a vein that runs up the left side of the vertebral column. This particular vein has several synonyms that are used interchangeably in the medical field. These synonyms include the hemiazygos vein, semiazygos vein, and the accessory hemiazygos vein. Each of these terms refers to the same vein, but they may be used in different medical contexts or depending on the preferences of individual medical professionals. Regardless of the terminology used, the vena hemizygos serves an important role in the circulatory system as it facilitates the movement of deoxygenated blood from the lower body to the heart.