Tensor fasciae latae muscle

Origin and insertion

The muscle originates from the outer lip of the anterior iliac crest and the anterior superior iliac spine. Distally its fibers attach to the fascia lata - a deep fascia surrounding the entire thigh musculature.

The tensor fasciae latae, the fibers of the gluteus maximus and the aponeurosis of the gluteus medius form a horizontal reinforcement known as the iliotibial tract. This band of connective tissue runs laterally over the knee joint and inserts at the lateral condyle of tibia and lateral patellar retinaculum.

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Relations

The tensor fasciae latae muscle is the most superficial muscle of the anterolateral aspect of the thigh. It is positioned lateral to the hip joint, immediately beneath the skin. In its superior aspect, tensor fasciae latae is found between the sartorius and gluteus medius muscle, where it overlays the gluteus minimus muscle. While descending down the thigh, the muscle is found between the two layers of fascia lata.
Due to its superficial position, this muscle is easily palpated. This is usually performed at the area located halfway between the anterior superior iliac spine and the greater trochanter of femur.

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Innervation

The innervation is supplied by the superior gluteal nerve (L4-S1) a branch of sacral plexus.

Blood supply

The tensor fasciae latae muscle is vascularized by the ascending branch of lateral circumflex femoral artery.

Function

The main task of the tensor fasciae latae is to sustain tension of the iliotibial tract. As the femoral shaft meets the pelvis, an angled pressure from above imposes a high bending strain to the femur. Both the hip abductors and the tensor fasciae latae counteract the pressure on the opposite side and help stabilize the bone (tension banding effect). Furthermore, the activation of the muscle leads to an abduction, flexion and internal rotation of the hip joint.

Contraction of the tensor fasciae latae muscle also causes external rotation of the leg at the knee joint. Furthermore, it aslo weakly flexes the leg, when there an existing degree of flexion greater than 20 degrees, and weakly extends the leg, when the angle of flexion is less than 20 degrees.

Finally, the TFL also works to stabilize both the hip and knee joints. 

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