Obturator internus muscle
Internal obturator muscle | |
---|---|
laterally rotates the extended hip and abducts the flexed thigh at the hip, and stabilizes the hip during walking | |
Identifiers | |
Latin | musculus obturatorius internus |
TA98 | A04.7.02.012 |
TA2 | 2605 |
FMA | 22298 |
Anatomical terms of muscle] |
The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis.
It exits the pelvic cavity through the lesser sciatic foramen.
The internal obturator is situated partly within the
It functions to help laterally rotate femur with hip extension and abduct femur with hip flexion, as well as to steady the femoral head in the acetabulum.
Structure
Origin
The internal obturator muscle arises from the inner surface of the antero-lateral wall of the
It also arises from the pelvic surface of the
Passage
The fibers converge through the lesser sciatic foramen.[1] These end in four or five tendinous bands, which are found on the deep surface of the muscle. These bands are reflected at a right angle over the grooved surface of the ischium between its spine and tuberosity.
The obturator nerve passes on the superficial surface of the internal obturator muscle.[3] The pudendal nerve passes on the lateral surface of the internal obturator muscle and the coccygeus muscle.[4] The sciatic nerve passes superficial to the internal obturator muscle on the posterior surface.[5][6]
Insertion
The tendon inserts on the greater trochanter of the proximal femur.[1]
Nerve supply
The internal obturator muscle is supplied by the
Bursa/bands
This bony surface is covered by smooth cartilage, which is separated from the tendon by a
These bands leave the pelvis through the lesser sciatic foramen and unite into a single flattened tendon, which passes horizontally across the capsule of the hip-joint, and, after receiving the attachments of the
A bursa, narrow and elongated in form, is usually found between the tendon and the capsule of the hip-joint. It occasionally communicates with the bursa between the tendon and the ischium.
Function
The internal obturator muscle helps to support the
Additional images
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Obturator internus muscle
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Obturator internus muscle
References
This article incorporates text in the public domain from page 477 of the 20th edition of Gray's Anatomy (1918)
- ^ ISBN 978-0-323-42878-1, retrieved 2021-03-04
- ISBN 978-0-443-10373-5, retrieved 2021-03-04
- ISBN 978-0-12-802653-3, retrieved 2021-02-27
- PMID 26003239, retrieved 2021-02-27
- ISBN 978-0-7216-9537-2, retrieved 2021-03-04
- PMID 23931789, retrieved 2021-03-04
- ISBN 978-0-7020-3131-1, retrieved 2021-03-04
External links
- Anatomy photo:13:st-0407 at the SUNY Downstate Medical Center - "Gluteal Region: Muscles"
- Anatomy photo:43:st-0603 at the SUNY Downstate Medical Center - "The Female Pelvis: Muscles"
- Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna
- pelvis at The Anatomy Lesson by Wesley Norman (Georgetown University) (femalepelvicdiaphragm, malepelvicdiaphragm)
- perineum at The Anatomy Lesson by Wesley Norman (Georgetown University) (analtriangle3)
- Int. J. Morphol., 25(1):95-98, 2007