Obturator+internus


 * Author: Sinead "Wildumlilo" Johnson**

toc =Description = The obturator internus is a fan shaped muscle, as its tendon turns through a right angle as it passes through the lesser sciatic foramen. The belly lies within the pelvis, forming the lateral wall of gluteal region and the hip joint muscle group. It also forms the anterolateral wall of the pelvic cavity. It is located in the gluteal region deep to the gluteus maximus. It originates from the medial surface of the pubis, around the obturator foramen and the medial surface of the obturator membrane. The muscles fibres pass posteriorly and then turn through a right angle below the ischial spine through the lesser sciatic foramen. It then posteriorly and inferiorly to the hip joint to insert at the medial surface of the upper border of the greater trochanter of the femur anterior to piriformis. The nerve supplying this muscle is a branch from the sacral plexus, named the nerve to obturator internus (L5 to S2). The blood supply comes from the internal pudendal vessels and superior inferior gluteal arteries. The muscle forms part of the six lateral rotators in the gluteal region, therefore it rotates the thigh laterally at the hip joint, stabilizes the hip and helps with abducting a flexed hip.

=Interactions and relations to other Muscles = Obturator internus muscle lies in the gluteal region deep to gluteus maximus, gluteus medius and gluteus minimus. The tendon of this muscle lies between gemellus superior and gemellus inferior. The tendon of the muscle is directly inferior to gemellus superior and directly superior to gemellus inferior. Obturator internus performs actions with the six deep lateral rotator hip muscles (of which obturator internus is also included), which are piriformis , gemellus superior, gemellus inferior, obturator externus and quadratus femoris. The antagonizing muscle of obturator internus is gluteus minimus as it antagonizes the movement of lateral rotation of the hip.

=Relevance to Physiotherapy =

The obturator internus muscle has relevance to physiotherapy in terms of pelvic myoneurpathy which is pelvic pain. This ailment is commonly mistaken for prostatitis in men and menstrual pain in females. Due to the fact that the obturator internuscommonly inserts on the pubic bone it has an effect on the urethra. Pelvic pain could be caused by posture abnormalities such as kyphosis and lordosis, the physiotherapist plays the role in doing an evaluation and prescribing muscle exercises and myofascial trigger point therapy to relieve the pelvic pain. The obturator internus is also affected by the piriformis and sciatic nerve which is often inflamed and the muscle spasm and trigger points of the piriformis due its proximity. The physiotherapist would then assess the situation and provide relevant treatment.

=<span style="font-family: Arial,Helvetica,sans-serif;">Links to online interactive material = <span style="font-family: Arial,Helvetica,sans-serif;">[|The shape and location in 3D] media type="youtube" key="7IGC4vHQaxE" height="315" width="420"

media type="youtube" key="Y8VKY5PT0c8" height="315" width="420" =References= [] [] @http://cueflash.com/decks/Hip_and_Thigh_Muscles Muscolino, J.E., (2005). //The Muscular System Manuel: The skeletal muscles of the human body 2nd Edition.// London: Elsevier Mosby Dykes, M. (2002). //Crash Course: Anatomy 2nd Edition.// London: Elsevier Mosby Anne, M.R., (2005). //Grants Atlas Of Anatomy 11th Edition.// USA @http://www.chronicprostatitis.com/myoneuropathy.html []