Final answer:
The medical directional term that means "situated toward the tail" and is synonymous with posterior is 'caudal'.
Step-by-step explanation:
The term you're looking for that means "situated toward the tail" and is a synonym for posterior is caudal. In medical and anatomical terminology, caudal or inferior refers to a position below or lower than another part of the body, near or toward the tail end of the body's axis. For example, the pelvis is caudal to the abdomen. This term is used to provide a clear directional context within the body which is essential in medical descriptions and during procedures.