The middle rectal vein is a medical term used to describe a specific vein in the body. There are a few synonyms that can be used interchangeably to describe this vein. One option is the rectal middle vein, which simply switches the order of the words. Another possible synonym is the intermediate rectal vein, which conveys a similar meaning to middle. Some medical professionals may also refer to it as the median rectal vein, which references a central position. Ultimately, all of these terms are referring to the same vein in the body, which is an important part of the vascular system.