The adductor muscles of the medial compartment of the thigh are arranged in three layers: i) the superficial layer consisting of pectineus and adductor longus muscles, ii) the middle layer represented by the adductor brevis muscle, and iii) the deep layer formed by the obturator externus and adductor magnus muscles.
Once the posterior division of the obturator nerve entered the thigh, it descended deep to the pectineus and the adductor brevis, within the fascial layer overlying the obturator externus and the proximal part of the adductor magnus muscles.
Several studies have been published that describe various sites at which the obturator nerve branches into anterior and posterior divisions : a) near the obturator foramen, (6,25) b) within the obturator canal, (26,27) c) at the exit from the obturator canal, (28) and d) at the proximal border of the adductor brevis muscle.
Others demonstrate the anterior division descending superficial to the obturator externus muscle, and the posterior division traversing the midpoint of the same muscle and running downward, behind the adductor brevis and in front of the adductor magnus muscles.
Then it passes anterior to the adductor magnus muscle, dividing into branches to adductor magnus and occasionally the adductor brevis.