The rectus femoris is one of the key muscles in walking and has been shown to fire independently from other quadriceps muscles. Interestingly, the indirect tendon is often forgotten, even though it is the first insertion during embryonic development. Its well-known functions are extending the knee, flexing the hip, and stabilizing the pelvis on the femur during weight-bearing activities.

The rectus femoris in its nature is predisposed to injury, due to eccentric loading with maximal lengthening during sprinting and kicking. Most proximal injuries are myotendinous and myoaponeurotic, however avulsion or ruptures may also be seen in clinical practice. The indirect tendon is more frequently reported in these occasions than direct or the conjoined tendon. The diagnosis of the indirect tendon ruptures is vital for clinical practice due to longer rehabilitation times. Furthermore, it is proposed that indirect tendon ruptures progress to the direct head to the conjoined tendon.