Lower Limb LO4
4. Describe the deep fascia of the lower limb, and give an example of a specialization of this fascia.
The deep fascia of the limbs envelopes the muscles and separates the muscles into compartments associated with each segment of the limb. The muscles are “collected” into compartments or groups of muscle by portions of deep fascia, and typically separated by intermuscular septa.
The deep fascia of the lower limb has many functions, but of particular importance is resistance of excessive muscle expansion during contraction. This allows the muscles to compress the veins, and assists venous valves in directing blood flow towards the heart.
The deep fascia of the lower limb is called the fascia lata in the thigh and crural fascia in the leg. In specific areas, this fascia is thickened and serves specialized functions. Important examples in the lower limb are:
- iliotibial (IT) tract/band: a thickening of the fascia lata that stretches from the lateral side of the crest of the ilium to attach to the lateral condyle of the tibia.
- retinacula of the patella: thickened/reinforced portions of the crural fascia from the patella to the medial and lateral condyles of the tibia and the head of the fibula.
The lower limb, due to typically tight closure of the fascial compartments, are more susceptible to compartment syndromes. Compartment syndromes can be caused by trauma to any structures within the compartment, which may lead to inflammation, hemorrhage, and edema. This can lead to entrapment or compression of structures within. The anterior leg compartment is particularly susceptible to this type of syndrome.