The
iliotibial tract or
iliotibial band (also known as Maissiat's band or IT Band) is a longitudinal fibrous reinforcement of the
fascia lata. The action of the ITB and its associated muscles is to extend, abduct, and laterally rotate the hip. In addition, the ITB contributes to lateral knee stabilization. During knee extension the ITB moves anterior, while knee flexion moves the ITB posterior. It originates at the anterolateral
iliac tubercle portion of the external lip of the
iliac crest and inserts at the
lateral condyle of the
tibia at
Gerdy's tubercle. The figure shows only the proximal part of the iliotibial tract.