Semitendinosus muscle

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Semitendinosus muscle
Muscles of the gluteal and posterior femoral regions. (Semitendinosus visible at bottom left.)
Semitendinosus visible at bottom right.
Latin musculus semitendinosus
Gray's subject #128 479
Origin:
Insertion:
Blood:
Nerve: sciatic nerve
Action:
Dorlands/Elsevier m_22/12550732

The semitendinosus is a muscle in the back of the thigh; it is one of the hamstrings.


Contents

[edit] Structure

The semitendinosus, remarkable for the great length of its tendon of insertion, is situated at the posterior and medial aspect of the thigh.

It arises from the lower and medial impression on the tuberosity of the ischium, by a tendon common to it and the long head of the biceps femoris; it also arises from an aponeurosis which connects the adjacent surfaces of the two muscles to the extent of about 7.5 cm. from their origin.

The muscle is fusiform and ends a little below the middle of the thigh in a long round tendon which lies along the medial side of the popliteal fossa; it then curves around the medial condyle of the tibia and passes over the tibial collateral ligament of the knee-joint, from which it is separated by a bursa, and is inserted into the upper part of the medial surface of the body of the tibia, nearly as far forward as its anterior crest.

At its insertion it gives off from its lower border a prolongation to the deep fascia of the leg and lies behind the tendon of the sartorius, and below that of the gracilis, to which it is united. These three tendons form what is known as the pes anserinus, so named because it looks like the foot of a goose.

A tendinous intersection is usually observed about the middle of the muscle.

[edit] Innervation

The semitendinosus is innervated by the tibial part of the sciatic nerve.

[edit] Actions

The semitendinosus helps to extend (straighten) the hip joint and flex (bend) the knee joint. It also helps medially rotate the knee.

[edit] Additional images

[edit] See also

[edit] External links

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 As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

Muscles of the HeadNeckTrunkUpper limbLower limbLIST OF ALL MUSCLES

ILIAC REGION/HIP FLEXORS: psoas major | psoas minor | iliacus | (Gray's s127)

THIGH: anterior femoral | sartorius | quadriceps (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) | articularis genu
medial femoral/adductor | gracilis | pectineus | adductor brevis | adductor longus | adductor magnus
gluteal region | gluteals (maximus, medius, minimus) | tensor fasciae latae
lateral rotator group | piriformis | obturator externus | obturator internus | inferior gemellus | superior gemellus | quadratus femoris
posterior femoral/hamstring | biceps femoris | semitendinosus, semimembranosus | (Gray's s128)

LEG: anterior crural | tibialis anterior | extensor hallucis longus | extensor digitorum longus | fibularis tertius
superficial posterior crural | calf (gastrocnemius, soleus) | plantaris
deep posterior crural | popliteus | flexor hallucis longus | flexor digitorum longus | tibialis posterior
lateral crural | fibularis longus | fibularis brevis | (Gray's s129)

FOOT: dorsal | extensor digitorum brevis | extensor hallucis brevis
plantar first layer | abductor hallucis | flexor digitorum brevis | abductor digiti minimi
plantar second layer | quadratus plantae | lumbrical muscle
plantar third layer | flexor hallucis brevis | adductor hallucis | flexor digiti minimi brevis
plantar fourth layer | dorsal interossei | plantar interossei | (Gray's s131)

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