Iliotibial tract
Tractus iliotibialis
Also known as: iliotibial band, IT band, ITB, fascia lata
A thick lateral band of the fascia lata running from the iliac crest to Gerdy's tubercle on the tibia. It serves as the shared aponeurotic tendon of gluteus maximus and TFL.
Overview
The fascia lata, the deep fascia of the thigh, is thickened laterally into the iliotibial tract (ITT). The ITT runs from the iliac tubercle of the iliac crest down the lateral thigh, crosses the lateral femoral epicondyle and inserts on the anterolateral tibia at Gerdy's (iliotibial) tubercle. It is anchored to the linea aspera by the lateral intermuscular septum. It receives most of gluteus maximus and all of TFL, making it their common aponeurotic tendon.
It braces the lateral side of the thigh and helps stabilise both the hip (resisting adduction in single-leg stance) and the extended knee. It also stores elastic energy during running. With the knee extended it lies in front of the transverse knee axis, but as the knee flexes past ≈30° it moves behind the axis.
Anatomy
- Origin
Iliac tubercle and anterior iliac crest (via the fascia lata, TFL and gluteus maximus).
- Insertion
Gerdy's tubercle on the anterolateral condyle of the tibia.
- Relations
Superficial to vastus lateralis. Crosses the lateral femoral epicondyle with an intervening fat pad or bursa.
Function
- Transmits the force of gluteus maximus and TFL to the tibia
- Stabilises the lateral hip and the extended knee
- Lateral tension band for the femur
Clinical significance
Iliotibial band syndrome
An overuse injury in runners and cyclists. Friction or compression of the ITT over the lateral femoral epicondyle at ≈20–30° of knee flexion causes lateral knee pain (positive Noble test). Managed with load reduction and strengthening of the hip abductors.
External snapping hip
The ITT or the anterior border of gluteus maximus flicks over the greater trochanter, producing an audible snap.
Compiled from standard anatomy and physiology references — see the Muscular System sources. For education only; not medical advice.