The literature review of the present study demonstrated that the rotator cuff muscle group is composed of a complex architecture that is still difficult to understand in its entirety. By analyzing articles preferably from the last five years, we concluded that all four muscles can have anatomical variations ranging from the absence of multiple bellies to the presence of multiple bellies. Unlike what the classical literature cites as the rotator cuff being composed of muscles from only one belly, we conclude that all four muscles can have anatomical variations ranging from the absence of to the presence of multiple belly and muscle fusions. This is extremely important in the surgical planning of this region, aiming at its integral composition and possible variations.