Tensor Fasciae Latae (TFL) Muscle Anatomy

Location & Overview

The tensor fasciae latae (TFL) is a muscle located in the proximal and anterolateral aspect of the thigh. It sits between the deep and superficial fibers of the iliotibial tract, also known as the iliotibial band (ITB). It belongs to the muscles of the gluteal region. Other muscles of this region are the gluteus maximus, gluteus medius and gluteus minimus ^{[1] [2]}.

Origin & Insertion

The tensor fasciae latae originates from the anterior superior iliac spine (ASIS) and the anterior aspect of the iliac crest. As it passes down the thigh, it attaches to the deep and superficial fascia of the iliotibial band. Due to this, the insertion point for the tensor fasciae latae is the iliotibial band. Once the tensor fasciae latae inserts into the iliotibial band, the iliotibial band continues down the leg, where it eventually crosses the knee joint and inserts onto the iliotibial tubercle (also known as Gerdy’s tubercle) ^{[3] [4] [5]}.

Actions

The TFL assists various muscles groups in the stabilisation and movement of the hip and knee joints. For example, it works with the gluteus medius and gluteus minimus during internal rotation and abduction of the hip. Both the gluteus maximus and TFL connect via an aponeurosis to the iliotibial tract and due to this the TFL is also able to work with the gluteus maximus to abduct the hip. In addition to abduction, it can also assist with flexion of the hip. However, the hip flexion the TFL provides is weak comparative to primary hip flexors, such as the rectus femoris and iliopsoas muscle group ^{[6] [7]}.

The TFL connects into the iliotibial tract via an aponeurosis. The iliotibial tract then inserts onto the iliotibial tubercle (also known as Gerdy’s tubercle). Due to this, contraction of the TFL can contribute to flexion of the knee joint (because the iliotibial tract crosses the knee joint). However, the TFL can only contribute to knee flexion beyond approximately 30 degrees. This connection of the TFL to the tibia via the iliotibial tract is how it can assist in stabilisation of the knee joint. The TFL can also act on the iliotibial tract to assist in lateral rotation of the tibia ^{[8] [9]}.

A function of the TFL is to assist in walking. When the TFL contracts it weakly pulls the ilium inferiorly (hip abduction). This contraction then assists in lifting the hip on the opposite side. This is particularly useful when walking because during the swing phase of gait, it allows the leg to swing through without hitting the ground ^{[10] [11]}.

Innervation

The TFL is innervated by the superior gluteal nerve (L4, L5, S1) which is a branch of the sacral plexus ^[12].

Blood Supply

Blood is supplied to the TFL via the deep branch of the superior gluteal artery ^[13].