Posterior muscular branches of obturator nerve

The posterior muscular branche of obturator nerve pierces the anterior part of the Obturator externus, and supplies this muscle; it then passes behind the Adductor brevis on the front of the Adductor magnus, where it divides into numerous muscular branches which are distributed to the Adductor magnus and the Adductor brevis when the latter does not receive a branch from the anterior division of the nerve. It usually gives off an articular filament to the knee-joint

Note that the obturator nerve supplies only the adductor part of the adductor magnus, while its ischiocondylar part is supplied by the tibial division of the sciatic nerve.