obturator externus muscle


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ob·tu·ra·tor ex·ter·nus mus·cle

(ob-tū-rā'tōr eks-ter'nŭs mŭs'ĕl)
Origin, lower half of margin of obturator foramen and adjacent part of external surface of obturator membrane; insertion, trochanteric fossa of greater trochanter; action, rotates thigh laterally; nerve supply, obturator.
Synonym(s): musculus obturatorius externus [TA] , external obturator muscle.
References in periodicals archive ?
MRI revealed high grade right obturator internus and obturator externus muscle strain involving the attachments to the obturator ring and ischium (Figure 2).
It passes through the following structures in the following order: gracilis, adductor brevis muscle, obturator externus muscle, obturator membrane, and beneath or through the obturator internus muscle and periurethral endopelvic connective tissue; it finally exits through the opened vagina.
After preparation of the space between the anteroinferior capsule and the psoas tendon, the ischium is approached proximal to the obturator externus muscle.
The obturator externus muscle was carefully removed from its origin and the contents of the obturator canal were dissected out.
The obturator externus muscle is the deepest muscle of the superomedial part of the thigh.
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 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.
In the current anatomic study, it was found that in most cases, prior to entering the obturator canal, the obturator nerve gave off branches to the obturator artery, periosteal nerve branches and the nerve to obturator externus muscle, and then divided into the anterior and posterior divisions.
In 32 lower limbs, the posterior and anterior divisions of the obturator nerve emerged into the thigh anterior to the obturator externus muscle and its fascia, accompanied by the branches of the obturator artery and vein (Figure 2).
In 22 lower limbs, the posterior division of the obturator nerve, after exiting the canal, descended posterior to the proximal quarter of the obturator externus muscle and its fascia.
However, the first ischial cut can be easily performed prior to repositioning through the lateral incision, between the inferior gemellus and obturator externus muscles, with optimal visual control of the sciatic nerve.