Structure and Borders
The fascia lata surrounds the muscles of the entire thigh and presents the following boundaries and features:
- Superiorly: Blends with the inguinal ligament (lig. inguinale).
- Posteriorly: Continuous with the gluteal fascia.
- Inferiorly: Extends downward to merge with the crural fascia (fascia cruris), which is thinner anteriorly and thicker posteriorly and medially.
- Surface: The lateral part is exceptionally dense. The fascia forms isolated sheaths for superficial muscles: the tensor fasciae latae (m. tensor fasciae latae), sartorius (m. sartorius), adductor longus (m. adductor longus), and gracilis (m. gracilis).
Intermuscular Septa
The fascia sends deep septa into the thigh, creating isolated compartments for muscle groups:
- Lateral intermuscular septum (septum intermusculare femoris laterale): A strong sheet at the lateral boundary of the region. It separates the anterior and posterior fascial compartments.
- Posterior intermuscular septum (septum intermusculare femoris posterior): Covers the posterior surface of the adductor magnus muscle. It separates the posterior fascial compartment from the medial compartment.
Iliotibial Tract
On the lateral surface of the thigh, the fascia thickens to form the iliotibial tract (tractus iliotibialis).
- Origin: From the iliac crest (crista iliaca) and the aponeuroses of the gluteus maximus (m. gluteus maximus) and tensor fasciae latae (m. tensor fasciae latae) muscles.
- Insertion: Anterior to the lateral tibial condyle (Gerdy's tubercle).
- Function: Stabilizes the knee joint in the sagittal plane, acting as a "passive stabilizer" during running and walking. Contracture of the m. tensor fasciae latae disrupts this stabilization.
Topography and Neighboring Structures
The fascia lata is closely associated with the neurovascular and lymphatic structures of the thigh:
- Saphenous opening (hiatus saphenus): An opening in the fascia where the cribriform fascia (lamina cribrosa) is formed. The great saphenous vein (v. saphena magna) passes through it to drain into the femoral vein, along with lymphatic vessels. The femoral canal also opens here.
- Lymph nodes: Superficial inguinal lymph nodes (nodi lymphoidei inguinales superficiales) lie superficial to the fascia lata and are divided into superomedial, superolateral, and inferior groups. Deep inguinal nodes are located beneath the fascia, on the anterior wall of the femoral vein.
- Nerves: Superficial branches of the femoral nerve (rr. cutanei anteriores) pierce the fascia lata through the sartorius muscle sheath to supply the skin.
- Bursae: The subcutaneous prepatellar bursa (bursa subcutanea prepatellaris) is located on the anterior surface of the knee; it is an important clinical landmark and is frequently inflamed in occupations involving prolonged kneeling.
Clinical Significance
Due to its strength and surface area, the fascia lata is widely used as a graft material in surgery:
- Neurosurgery: In decompressive craniectomy for severe cerebral edema or extensive ischemic stroke, a fascial patch is sutured into the dura mater. This allows the edematous brain to expand outward, preventing a fatal increase in intracranial pressure.
- Maxillofacial Surgery: A strip of fascia lata measuring 3 × 10 cm can be transplanted in combination with muscle flaps from the masseter muscle to restore mobility to the lower lip during reconstructive surgery.