At the upper and medial part of the thigh, a little below the medial end of the inguinal ligament, is a large oval-shaped aperture in the fascia lata; it transmits the great saphenous vein, and other, smaller vessels, and is termed the the saphenous opening (fossa ovalis).
The fascia cribrosa, which is pierced by the structures passing through the opening, closes the aperture and must be removed to expose it. The fascia lata in this part of the thigh is described as consisting of a superficial and a deep portion.
The superficial portion of the fascia lata is the part on the lateral side of the fossa ovalis. It is attached, laterally, to the crest and anterior superior spine of the ilium, to the whole length of the inguinal ligament, and to the pectineal line in conjunction with the lacunar ligament. From the tubercle of the pubis it is reflected downward and lateralward, as an arched margin, the falciform margin, forming the lateral boundary of the fossa ovalis; this margin overlies and is adherent to the anterior layer of the sheath of the femoral vessels: to its edge is attached the fascia cribrosa. The upward and medial prolongation of the falciform margin is named the superior cornu; its downward and medial prolongation, the inferior cornu. The latter is well-defined, and is continuous behind the great saphenous vein with the pectineal fascia.
The deep portion of fascia latat is situated on the medial side of the fossa ovalis, and at the lower margin of the fossa is continuous with the superficial portion; traced upward, it covers the Pectineus, Adductor longus, and Gracilis, and, passing behind the sheath of the femoral vessels, to which it is closely united, is continuous with the iliopectineal fascia, and is attached to the pectineal line.
From this description it may be observed that the superficial portion of the fascia lata lies in front of the femoral vessels, and the deep portion behind them, so that an apparent aperture exists between the two, through which the great saphenous passes to join the femoral vein.