It arises from: i) the margins of the obturator foramen, ii) pubic and ischial rami, and iii) the external surface of the obturator membrane, the tendinous aponeurotic arch which completes the obturator canal. The muscle passes inferior to the acetabulum to attach to the trochanteric fossa.
The superior free edges of the obturator internus muscle and its fascia, the obturator membrane (between the anterior and posterior obturator tubercles), and the obturator externus muscle and its fascia collectively form the musculotendinous aponeurotic arch which converts the obturator groove into an obturator canal. The direction of the canal is i) from superior to inferior, ii) from lateral to medial, and iii) from posterior to anterior.
The contents of the obturator canal include: i) superomedially, nerve to obturator externus muscle, and obturator artery, ii) inferomedially, obturator vein, and iii) superolaterally, anterior and posterior divisions of the obturator nerve, which lay within the obturator groove.
Within the obturator canal, the posterior division of the obturator nerve is bound superiorly by the anterior division of the nerve, and inferiorly by the obturator artery and the nerve to obturator externus muscle.