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Tensor fasciae latae
A short muscle at the front of the hip that puts tension into the iliotibial band running down the outside of the thigh.
Latin name: Musculus tensor fasciae latae. In plain English, the small front-of-hip muscle that tightens the IT band. It is filed here under hip and buttock.
Reference information, not a diagnosis. Where a symptom is described below, it is there so you can describe your own more precisely to a clinician — not so you can name what you have.
Where it is
Tensor fasciae latae is a small muscle at the front outer corner of the hip, arising from the bony point you can feel at the front of the pelvis. It is short — it ends within the upper third of the thigh — but its tendon is a long one: the iliotibial tract, a thick strip of fascia running the whole length of the outer thigh to the outside of the shin bone just below the knee.
The tract also receives fibres from gluteus maximus behind, so it is tensioned from two directions. It is firmly anchored to the femur along the way, which is why the old picture of it sliding freely back and forth over the bone has been revised.
| Feature | Detail |
|---|---|
| Origin | Anterior superior iliac spine and the adjacent outer lip of the iliac crest |
| Insertion | Iliotibial tract, about a third of the way down the thigh; the tract continues to Gerdy tubercle on the lateral tibia |
| Nerve | Superior gluteal nerve (L4-S1) |
| Main actions | Flexion, abduction and internal rotation of the hip; tensions the iliotibial tract to help stabilise the knee |
What it does
It flexes, abducts and internally rotates the hip, and it puts tension into the iliotibial tract, which in turn stabilises the knee against sideways movement. In gait it works with gluteus medius and minimus to control the pelvis during single-leg stance, though it is much smaller and less able to do that job alone.
Iliotibial band syndrome, one of the most common causes of lateral knee pain in runners and cyclists, was long explained as the band rubbing back and forth over the lateral femoral epicondyle. Anatomical work has made that unlikely, because the band is anchored to the femur and does not really slide. The current explanation is compression of the fat and connective tissue underneath it near the knee, which fits the symptom of pain at a repeatable knee angle during running.
Exercises that load it
| Exercise | Category | Muscles the exercise library lists |
|---|---|---|
| Easy running (8 km/h) | Cardio | Legs, heart, lungs |
| Cycling (19-22 km/h) | Cardio | Quads, glutes, calves, heart |
| Stair climbing | Cardio | Quads, glutes, calves, heart |
| Brisk walking (5.5 km/h) | Cardio | Legs, heart |
It is loaded in every stride and every pedal stroke, and it takes on more when the larger hip abductors are not doing their share. Training the hip abductors properly with single-leg work is the usual approach: give gluteus medius the strength to do its job and this small muscle has less reason to overwork.
How it is lengthened
Standing with the leg to be stretched crossed behind the other, push the hip outward and side-bend away. Foam rolling the outer thigh is popular, and it does reduce perceived tightness in the short term, but it does not lengthen the iliotibial band — the band is far too strong for hand pressure to deform lastingly. Rolling directly over the painful spot at the knee often aggravates it.
When it goes wrong
| Problem | What it typically feels like | Usual setting |
|---|---|---|
| Iliotibial band syndrome | Sharp or burning pain on the outside of the knee that comes on at a predictable point in a run and eases with rest | Running, especially downhill or on a cambered surface, and cycling with a poor saddle position |
| Anterolateral hip ache | A dull ache at the front outer hip, worse after long walks or hill work | Overuse of the small hip abductor when the larger ones are weak |
| Snapping hip, lateral type | A snap or clunk at the outer hip as the band flicks over the greater trochanter | Repeated hip flexion and extension, common in dancers and runners |
Knee pain that comes with swelling, locking, giving way or an inability to bear weight is not iliotibial band syndrome and needs a proper examination.
Nothing on this page is a treatment plan. If a problem is limiting what you do, is not improving, or is getting worse, the right next step is an assessment by a doctor or a physiotherapist who can examine you.
Sources: descriptive anatomy from Gray's Anatomy of the Human Body, 20th US edition (1918), which is in the public domain; Latin names follow Terminologia Anatomica, published by the Federative International Programme for Anatomical Terminology. Nerve root levels are the conventional ranges taught from those sources and vary between individuals and between textbooks. Exercise cross-links use the TempoLife exercise library. Checked 2026-09-06.
Frequently asked questions
Can you stretch the IT band?
Not meaningfully. It is a dense fascial sheet with tensile strength comparable to a strong tendon, and it is anchored to the femur along its length. What changes with stretching and rolling is the sensation and the tone of the muscles attached to it, not the length of the band.
Why does IT band pain come on at the same point in every run?
Because the mechanism is compression at a particular knee angle, repeated at every stride. Once the tissue is irritated, the same number of strides tends to reproduce it.
Should I foam roll the outside of my thigh?
It can feel helpful and it is unlikely to do harm along the mid-thigh. Rolling directly on the painful area next to the knee tends to aggravate a compressive problem.
Nearby in this reference
Iliopsoas
The deep hip flexor that runs from the lower spine to the thigh
Gluteus maximus
The main buttock muscle
Gluteus medius
The side-hip muscle that keeps the pelvis level
Piriformis
The deep rotator behind the hip, next to the sciatic nerve
Hip adductors
The inner thigh muscles
Deltoid
The cap of the shoulder
All 34 body parts · Exercise library · Body map
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