Saphenous Nerve with an Unusual Branching Pattern: A Case Report and Literature Discussion

The saphenous nerve is one of the terminal branches of the femoral nerve, originating from the L2, L3, and L4 roots. It is a sensory nerve responsible for the innervation of the medial and inferior aspects of the thigh, as well as the medial region of the leg and the knee. The saphenous nerve was dissected from its origin to its termination in a 56 kg male cadaver previously fixed with formaldehyde. Basic surgical instruments were used for the procedure. Measurements were obtained using electronic calipers and rulers, and images were captured using a Nikon D500 camera. The saphenous nerve bifurcated 14.17 cm from its origin into medial and lateral branches. The medial branch (branch 1) extended toward the medial region of the leg and, at 9 cm from its origin, formed a loop or foramen with a maximum length of 2.9 cm, allowing the passage of a perforating vein. The lateral branch (branch 2) followed the typical course, bifurcating 17.9 cm from its origin into a larger lateral branch that traversed the distal insertion tendon of the sartorius muscle, and a medial branch that gave rise to several small nerve filaments supplying the knee. We interpret the initial bifurcation as an atypical high terminal division of the nerve into its terminal branches: the infrapatellar branch (branch 2) and a sensory component composed of fibers from the terminal tibial branch and the femoral and tibial collateral branches described by Rouvière (branch 1).