The NEPs of pectineus, gracilis, adductor longus, adductor brevis and adductor magnus were labelled as NEP1, NEP2, NEP3, NEP4 and NEP5 respectively.
Gross anatomy observation: The trunk of the obturator nerve passes through the obturator externus muscle about 3 cm inferiolaterally to the pubic tubercle and divides into anterior and posterior branches, both of which travel superficial (anterior branch) and deep (posterior branch) to the adductor brevis muscle.
In this manuscript, we will use the NEP of adductor brevis muscle (NEP4) as a representative for analysis (Fig.
chose the line joining the synchondroses pubis and the medial femoral condyle as the reference line on body surface, and then measured the position of the motor points of gracilis, adductor longus, adductor brevis and adductor magnus muscle on the reference line.
1 = Pectineus muscle, 2 = PMB belongs to femoral nerve, 3 = Gracilis muscle, 4 = GMB, 5 = Adductor longus muscle, 6 = ALMB, 7 = Adductor brevis muscle, 8 = ABMB, 9 = Adductor magnus muscle, 10 = AMMB.
1 = gracilis muscle branch of the obturator nerve; 2 = adductor longus muscle branch; 3 = adductor brevis
muscle branch; 4 = adductor magnus muscle branch; 5 = pectineus muscle branch; 6 = femoral nerve trunk.
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.
Then it passes anterior to the adductor magnus muscle, dividing into branches to adductor magnus and occasionally the adductor brevis. Its terminal articular branch, traversing the adductor hiatus, enters the popliteal fossa to supply the articular capsule, cruciate ligaments, and synovial membrane of the knee joint.
Muscular nerve branches of the posterior division of the obturator nerve perforate the fascial layer in order to supply the obturator externus, adductor brevis, and anterior part of the proximal adductor magnus muscles, and may be susceptible to entrapment at the points of perforation.