Obturator foramen

Bone: Obturator foramen
Pelvis. Obturator foramen is 7.
Symphysis pubis exposed by a coronal section. Obturator canal labelled at center.
Latin	foramen obturatum
Gray's	subject #57 237

The obturator foramen is the hole created by the ischium and pubis bones of the pelvis through which nerves and muscles pass.

General structure

It is bounded by a thin, uneven margin, to which a strong membrane is attached, and presents, superiorly, a deep groove, the obturator groove, which runs from the pelvis obliquely medialward and downward.

This groove is converted into the obturator canal by a ligamentous band, a specialized part of the obturator membrane, attached to two tubercles:

• one, the posterior obturator tubercle, on the medial border of the ischium, just in front of the acetabular notch
• the other, the anterior obturator tubercle, on the obturator crest of the superior ramus of the pubis

Through the canal the obturator vessels and obturator nerve pass out of the pelvis.

For etymology see obturate and foramen.

Variations

Reflecting the overall gender differences between male and female pelvises, the obturator foramina are round in the male and oval in the female.

Additionally, unilateral pelvis hypoplasia can cause differences in size between the obturator foramina, and there are even rare reports of individual pelvises featuring a double obturator foramen in one of the hip bones.^[1]

See also

• Obturator internus muscle
• Obturator externus muscle

Additional images

Radiograph of a healthy human hip joint	Right hip bone. External surface.	Male pelvis.	Human female pelvis, viewed from front.
The two circles at the bottom are the obturator foramina.	Variations in origin and course of obturator artery.	The relations of the femoral and abdominal inguinal rings, seen from within the abdomen. Right side.

References

• This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.

1. ^ Apostolos Karantanas, Konstantina Velesiotou, and Evagelos Sakellariou (2002). "Double Obturator Foramen". Larissa General Hospital, Greece. http://www.ajronline.org/cgi/content/full/178/1/245. 

External links

• SUNY Labs 17:st-0205 - "Major Joints of the Lower Extremity: hip and sacrum (anterior view)"
• Atlas of anatomy at UMich male_urethrogram - "Pelvis & Perineum: Male Urethrogram"
• Photo at vc.cc.tx.us

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