Internal rotation refers to the movement of a body part, such as the leg or shoulder, towards the center or midline of the body. There are several synonyms for internal rotation, including medial rotation, inward rotation, and endorotation. The term medial rotation emphasizes the direction of movement towards the midline, while inward rotation emphasizes the movement towards the body's center. Endorotation is another term used in reference to internal rotation, emphasizing the rotation towards the inside of a joint. Although these terms have slightly different connotations, they are often used interchangeably to describe the same movement.