Morphometry and Functional Topography of the Pes Anserinus Complex: A Standardized Cadaveric Study.

PURPOSE: The pes anserinus (PA) is a tendinous complex located on the anteromedial proximal tibia and formed by the sartorius (SART), gracilis (GRT), and semitendinosus (STT) tendons. Published studies report heterogeneous measurement definitions and wide morphometric ranges. The present study aimed to establish standardized, population-based reference values using a single dissection and measurement protocol. METHODS: The PA was dissected in 62 formalin-fixed adult lower limbs (35 left, 27 right) from 41 cadavers (19 females, 22 males). Using the tibial tuberosity as a consistent landmark, we measured visible tendon length, footprint width, insertional thickness (SART) or diameter (GRT/STT), mid-tendon width (GRT/STT), distances from the tibial tuberosity to GRT and STT footprints, and inter-footprint spacing. Measurements were performed three times by two independent observers using electronic calipers. Sex-based comparisons were conducted. RESULTS: The STT was the longest tendon (145.25 ± 6.17mm), followed by the GRT (112.68 ± 5.45mm) and SART (59.15 ± 3.53mm). The GRT footprint was located closer to the tibial tuberosity than the STT footprint (32.54 ± 2.70mm vs 37.40 ± 3.41mm). Footprint widths differed substantially (SART 23.50 ± 3.97mm; STT 11.00 ± 1.08mm; GRT 7.46 ± 0.58mm). Inter-footprint distances demonstrated limited variability (STT-GRT 7.34 ± 0.92mm; GRT-SART 11.41 ± 2.47mm). In all specimens, the PA maintained a constant layered arrangement without pre-footprint fusion. CONCLUSIONS: Standardized cadaveric measurements demonstrate reproducible PA layering and provide population-based morphometric reference values for the anteromedial proximal tibia. These data support anatomical-functional interpretation of the medial knee stabilizing complex and may facilitate imaging-based and surgical anatomical orientation in procedures involving hamstring tendons.