The Sartorius muscle runs from the pelvis down to below the knee. It helps flex the hip and knee, aids in external hip rotation when the hip and knee flex, and abducts the hip by moving the ankles further apart when legs are kept straight. Stretching the Sartorius should produce tension along its path from the pelvis to below the knee.

1. Sartorius
The Sartorius is a small, ribbon-like muscle that runs from the
forward outside portion of your pelvis down to the inside of
your leg, just below the knee. It helps flex both the hip and
the knee. The Sartorius also aids in performing external hip
rotation as the hip and knee flex (think of turning your toes
out into a duck-walk position--that’s external hip rotation) and
abducts the hip (in other words, it moves your ankles further
apart from each other if you keep your legs straight

2. Stretches
You should feel
tension in here