Patients with lower back pain often have hip flexor tightness. The hip flexor that is very easy to locate is the sartorius due to its strap-like form stretching from the outer aspect of the hip to the medial aspect of the knee joint. This muscle allows us to sit in the taylor sit position or the lotus position.
The sartorius muscle flexes the hip as well as rolls the hip outward (external rotation). It is also a knee flexor.
To test this muscle, the patient places the heel of the tested side on the opposite knee. Patients with pain and tightness of the sartorius tend to have difficulty placing the heel on the opposite knee.
However, difficulty in performing this function also depends on presence of pain and spasm in the lower back muscles, hip extensor muscles, hip abductor and internal rotator muscles.
Tightness and shortening of these muscles will produce difficulty performing this motion which is also called the FABERE testing (this is a combination of ability of the hip to flex, abduct and externally rotate).
Nerve supply: Femoral nerve
Spinal segments: L2, L3 and L4 nerve roots