What is tensor fascia latae and what is the iliotibial band?
If you stand, walk, or run, the tensor fascia latae and iliotibial band (IT band) are critical structures for making that possible. In this article we’ll take a look at where these structures are, what they do, and how they work in conjunction with one another to make walking and running possible.
The tensor fascia latae is a muscle on the lateral, or outside, of your hip. The iliotibial band is not actually a muscle. It’s three layers of ligamentous fascia: a more superficial layer, an intermediate layer, and a deep layer. Its general function is to help maintain stability of the hip-to-knee-joint relationship when we put weight into our legs. It is often discussed alongside the tensor fascia latae because the tensor fascia latae, along with the gluteus maximus, controls the amount of tension in the IT band.
Let’s explore these structures in more detail.
Where is the tensor fascia latae and where is the IT band?
Both of these interrelated structures are located along the lateral side of the hip. The iliotibial band runs from the lateral hip along the lateral side of the leg all the way down until it crosses the knee joint.
Muscle attachments
Tensor fascia latae
The tensor fascia latae attaches proximally to the anterior iliac crest. Distally, it becomes fused with the fibers of the iliotibial band, generally just below the greater trochanter, but there is some variability from person to person with respect to the point at which the fusion of these structures occurs (Flack et al., 2012).
Iliotibial band
The iliotibial band is interwoven with multiple attachments at both ends. Based on its name you could guess that it attaches to both the ilium and the tibia, which is true.
More specifically, the IT band arises at the proximal end from fibers of the tensor fascia latae, the gluteus maximus, and the gluteal aponeurosis (a fibrous layer of fascia between the iliac crest and the gluteus maximus). Along its path, the iliotibial band attaches to the linea aspera, a linear area of rough textured bone on the femur that serves as an attachment site for several muscles. At its distal end, the iliotibial band attaches to: the distal linea aspera of the femur, the lateral epicondyle of the femur, the patella/patellofemoral ligament, and an area on the lateral tibia called Gerdy’s tubercle.
Muscle actions
Tensor fascia latae
The tensor fascia latae is sometimes grouped with the gluteus medius and gluteus minimus as a hip abductor muscle. However, its primary action is to stabilize the opposite hip from the one that is actually bearing weight, or that we are standing on, when walking, running, or standing. When it contracts it also affects the amount of tension in the IT band, and in that way, indirectly affects the stabilization of the knee.
Iliotibial band
The iliotibial band is a critically important structure for stabilizing the hip, and especially the knee joint, when we load weight into these joints. It functions to stabilize the joints and help distribute the load when we are weight-bearing in one or both legs, like we would be when standing, walking, or running, for example. Because of its location, the iliotibial band works in conjunction with the anterior cruciate ligament (ACL) to stabilize particularly the lateral and anterior sides of the knee joint.
The muscles into which the iliotibial band attaches at its proximal end, the tensor fascia latae and the gluteus maximus, influence the amount of shortness or tension that the IT band has. Simultaneous contraction of the lateral quadricep muscle, the vastus lateralis which runs laterally alongside the IT band, can also contribute to increasing the tension of the IT band.
The tensor fascia latae and the iliotibial band are critical structures in the body for making it possible for us to stand, walk, and run. If you’d like to know more about what structures support those actions, check out our related posts in this series: The Gluteus Medius And Gluteus Minimus Muscles, Iliotibial Band Syndrome, and The Lateral Hip Muscles In Running And Cycling.
References
Al-Hayani, A. 2009. The functional anatomy of hip abductors. Folia Morphologica. 68(2):98-103.
