Dimensions of Pes Anserinus of the Lower Extremity, an Anatomical Study with its Surgical Implications

The reconstructive surgeries utilize pes anserinus (PA) tendons, because of their lesser post-operative clinical deficits and donor site morbidity. These surgeries require anatomical knowledge about the extent of PA formation. The goal of this study was to determine the length and width of the PA formation. The objectives were to measure the distance of its upper limit, lower limit, and vertical distance from the tibial tuberosity (TT). The present descriptive cross sectional study included 53 embalmed cadaveric lower extremities. The upper and lower limits of PA were exposed with the careful dissection. Measurements of the dimensions were performed with the help of a digital vernier caliper (Mitutoyo Co., Kanagawa, Japan). The PA length, width, distance of its upper limit, lower limit, and vertical distance of it from the TT were 47.4±13.3 mm, 37.3±7.2 mm, 47.6±12.5 mm, 54.6±10.4 mm, and 39.1±14.2 mm, respectively over the right extremity. The same measurements were 46.3±14.7 mm, 39.1±9.4 mm, 39.1±5.9 mm, 49.5±8.2 mm, and 36.4±12.1 mm, respectively for the left extremity. The extent of PA was observed to be extremely variable. The preoperative knowledge about the dimensions of PA will help the plastic and orthopedic surgeon put the accurate skin incision, decreasing the donor site morbidity and biomechanical instability of the PA grafts. We suggest that, preoperative ultrasound measurement of the PA may help the operating surgeon to prevent the complications like injury to the infrapatellar branch of saphenous nerve.