Entrapment of the anterior division of the obturator nerve is a recently de
scribed cause of medial groin pain. This anatomic study examines the extrap
elvic course of the nerve and related fascia in the adductor region to prov
ide an anatomic basis for the syndrome and to aid in surgical treatment. Tw
elve anatomic specimen limbs were dissected to document the extrapelvic cou
rse of the obturator nerve, the myofascial arrangement, and the vasculature
, A thirteenth limb was prepared with intraarterial glycerin to examine the
vessels in more detail, A distinct fascial plane was found deep to the add
uctor longus and pectineus overlying the anterior division of the obturator
nerve. The arterial supply to the adductor muscles is related intimately t
o the nerve and its branches, with associated local thickening of the fasci
al connective tissue. The relationship between the nerve, vessels, and fasc
ia appears sufficient to result in an entrapment syndrome. The anatomic fin
dings from this series will help plan the surgical treatment of this condit
ion.