greater sciatic foramen


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Related to greater sciatic foramen: obturator foramen, Piriformis, pudendal nerve, Greater sciatic notch

greater sciatic foramen

The larger of two posterior openings into the bony pelvis. Along the back edge of the ilium and ischium bones, there are two semicircular indentations, the greater and lesser sciatic notches. Two crossed ligaments (the sacrotuberous and sacrospinous ligaments) make these notches into enclosed ovals, the greater and lesser sciatic foramena. The greater sciatic foramen is the upper and larger of these. The gluteal and some hip-joint structures, such as the piriformis muscle and the gluteal nerves and blood vessels, leave the pelvic cavity through this opening, as do the sciatic nerve and the posterior cutaneous nerve of the thigh.
See also: foramen
References in periodicals archive ?
In the sacral plexus, entrapment of the sciatic nerve at the greater sciatic foramen (piriformis syndrome) may be secondary to asymmetry of the piriformis muscle size or anatomic variations in the course of the sciatic nerve relative to the piriformis muscle (Figure Obtaining a sequence perpendicular to the piriformis muscle is crucial in identification of these anatomic variants.
PSA was seen as continuation of the left common iliac artery, passing out of the pelvis via the greater sciatic foramen. At the proximal one third of thigh, it was terminated spirally.
The persistent sciatic artery originates from the enlarged internal iliac artery which passes out of the pelvis via the greater sciatic foramen near the sciatic nerve.4 In our case, PSA was originated from left common iliac artery and passing out of the pelvis via the greater sciatic foramen [Fig-1 a,b,c].
It descends posteriorly to the superior margin of the greater sciatic foramen where it divides into an anterior trunk and a posterior trunk.
It runs laterally through the greater sciatic foramen, becomes tendinous, and inserts into the piriformis fossa at the medial aspect of the greater trochanter of the femur.

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