Obturator Nerve:

From: www.wheelessonline.com

- Anatomy:
     - formed from anterior branches of L2, L3, L4 (see innervation of muscles of the lower limb)
     - largest nerve formed from anterior divisons of  lumbar plexus ;
     - roots unite within the posterior part of psoas, & then descends thru psoas & runs downward over
            sacral ala into lesser pelvis, lying lateral to ureter & internal iliac vessels;
     - enters the upper part of the obturator foramen and then subsequently divides into
            anterior and posterior branches;

- Anterior Branch:
     - runs in front of obturator externus  & adductor brevis ;
     - it runs behind the   pectineus  and adductor longus muscles;
     - gives off articular twig that enters hip joint thru acetabular notch;
     - supplies muscular branches to hip adductors & then divides into cutaneous, vascular, and communicating vessels;

- Cutaneous Branch:
     - when present, it assists in innervation of skin and fascia over distal 2/3 of thigh;

- Posterior Branch:
     - pierces anterior part of obturator externus;
     - nerve then runs downward behind the adductor brevis & and in front of
             the adductor magnus;
     - it then splits into branches that are distributed to upper (adductor) part of adductor magnus  & sometimes to adductor brevis;