In peripheral nerve surgery, repair of the femoral nerve (FN) requires identification of normal nerve elements both proximal and distal to the level of the injury. We identified FN branches to the sartorius (SRT) and quadriceps muscles in 16 embalmed specimens and calculated the length of each branch to its point of entry into its respective muscle. The SRT and rectus femoris (RF) muscles were mobilized but not transected to mimic the surgical approach. Ratios of the length of each motor branch as a unit of the total length of the thigh, defined as the FN at the inguinal ligament to the superior margin of the patella were also calculated. The proximal branch to RF spanned a ratio of .19 ± .11 (mean ± standard deviation) from the FN at the inguinal ligament to its endpoint. The ratio of the distal branch to the RF was .29 ± .08. The ratio of the proximal SRT branch was .20 ± .05. The distal branch to SRT was located at a ratio of .43 ± .11. The proximal branch to vastus lateralis (VL) was .26 ± .08. The distal branch to VL was .39 ± .07. The ratio of the motor branch to vastus intermedius (VI) was .30 ± .05. Lastly, the branch to vastus medialis (VM) was .55 ± .06. The motor branch to SRT frequently emerged as a bifurcation of itself and saphenous nerve within the adductor canal. Knowledge of the relative location of the motor branches of the FN in the thigh can be helpful to surgeons during the nerve exploration and repair.
Keywords: femoral nerve; peripheral nerve surgery; surgical anatomy.