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Semimembranosus muscle

The semimembranosus muscle (/ˌsɛmiˌmɛmbrəˈnsəs/) is the most medial of the three hamstring muscles in the thigh. It is so named because it has a flat tendon of origin. It lies posteromedially in the thigh, deep to the semitendinosus muscle. It extends the hip joint and flexes the knee joint.

Semimembranosus muscle
Muscles of the gluteal and posterior femoral regions (semimembranosus labeled at bottom left)
Details
OriginIschial tuberosity
InsertionMedial condyle of tibia
ArteryProfunda femoris and gluteal arteries
NerveTibial part of sciatic nerve
(L5, S1 and S2)
ActionsExtension of hip and flexion of knee
AntagonistQuadriceps muscle and Tensor fasciae latae
Identifiers
Latinmusculus semimembranosus
TA98A04.7.02.036
TA22642
FMA22438
Anatomical terms of muscle
[edit on Wikidata]

Structure edit

 
Cross-section of thigh semimembranosus labelled bottom right

The semimembranosus muscle, so called from its membranous tendon of origin, is situated at the back and medial side of the thigh. It is wider, flatter, and deeper than the semitendinosus (with which it shares very close insertion and attachment points).[1] The muscle overlaps the upper part of the popliteal vessels.

Origin edit

The semimembranosus muscle originates by a thick tendon from the superolateral aspect of the ischial tuberosity.[1] It arises above and medial to the biceps femoris muscle and semitendinosus muscle. The tendon of origin expands into an aponeurosis, which covers the upper part of the anterior surface of the muscle; from this aponeurosis, muscular fibers arise, and converge to another aponeurosis which covers the lower part of the posterior surface of the muscle and contracts into the tendon of insertion.

Insertion edit

The semimembranosus muscle inserts on the:

The tendon of insertion gives off certain fibrous expansions: one, of considerable size, passes upward and laterally to be inserted into the posterior lateral condyle of the femur, forming part of the oblique popliteal ligament of the knee-joint; a second is continued downward to the fascia which covers the popliteus muscle; while a few fibers join the medial collateral ligament of the joint and the fascia of the leg.

Nerve supply edit

The semimembranosus is innervated by the tibial part of the sciatic nerve.[1] The sciatic nerve consists of the anterior divisions of ventral nerve roots from L4 through S3. These nerve roots are part of the larger nerve network–the sacral plexus.[2] The tibial part of the sciatic nerve is also responsible for innervation of semitendinosus and the long head of biceps femoris.

Variation edit

The semimembranosus muscle may be reduced or absent, or double, arising mainly from the sacrotuberous ligament and giving a slip to the femur or adductor magnus.

Function edit

The semimembranosus muscle extends (straightens) the hip joint. It also flexes (bends) the knee joint.[1]

It also helps to medially rotate the knee: the tibia medially rotates on the femur when the knee is flexed. It medially rotates the femur when the hip is extended. The muscle can also aid in counteracting the forward bending at the hip joint.[2]

Clinical significance edit

The semitendinosus muscle may be dry needled.[1]

Additional images edit

See also edit

References edit

  This article incorporates text in the public domain from page 479 of the 20th edition of Gray's Anatomy (1918)

  1. ^ a b c d e f g h i Sandalcidi, Dawn; Dommerholt, Jan (2013-01-01), Dommerholt, Jan; Fernández-de-las-Peñas, César (eds.), "10 - Deep dry needling of the hip, pelvis and thigh muscles", Trigger Point Dry Needling, Oxford: Churchill Livingstone, pp. 133–150, doi:10.1016/b978-0-7020-4601-8.00010-4, ISBN 978-0-7020-4601-8, retrieved 2021-03-01
  2. ^ a b Saladin, Kenneth S. Anatomy & Physiology: the unity of form and function. 5th ed. New York: McGraw-Hill, 2010. Print.

External links edit

  • Anatomy photo:14:st-0408 at the SUNY Downstate Medical Center
  • Anatomy figure: 14:01-07 at Human Anatomy Online, SUNY Downstate Medical Center - "Muscles (hamstrings) of the posterior compartment of the thigh."
  • Anatomy figure: 14:02-06 at Human Anatomy Online, SUNY Downstate Medical Center - "Muscles that form the superficial boundaries of the popliteal fossa."
  • knee/surface/surface4 at the Dartmouth Medical School's Department of Anatomy

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The semimembranosus muscle ˌ s ɛ m i ˌ m ɛ m b r e ˈ n oʊ s e s is the most medial of the three hamstring muscles in the thigh It is so named because it has a flat tendon of origin It lies posteromedially in the thigh deep to the semitendinosus muscle It extends the hip joint and flexes the knee joint Semimembranosus muscleMuscles of the gluteal and posterior femoral regions semimembranosus labeled at bottom left DetailsOriginIschial tuberosityInsertionMedial condyle of tibiaArteryProfunda femoris and gluteal arteriesNerveTibial part of sciatic nerve L5 S1 and S2 ActionsExtension of hip and flexion of kneeAntagonistQuadriceps muscle and Tensor fasciae lataeIdentifiersLatinmusculus semimembranosusTA98A04 7 02 036TA22642FMA22438Anatomical terms of muscle edit on Wikidata Contents 1 Structure 1 1 Origin 1 2 Insertion 1 3 Nerve supply 1 4 Variation 2 Function 3 Clinical significance 4 Additional images 5 See also 6 References 7 External linksStructure edit nbsp Cross section of thigh semimembranosus labelled bottom rightThe semimembranosus muscle so called from its membranous tendon of origin is situated at the back and medial side of the thigh It is wider flatter and deeper than the semitendinosus with which it shares very close insertion and attachment points 1 The muscle overlaps the upper part of the popliteal vessels Origin edit The semimembranosus muscle originates by a thick tendon from the superolateral aspect of the ischial tuberosity 1 It arises above and medial to the biceps femoris muscle and semitendinosus muscle The tendon of origin expands into an aponeurosis which covers the upper part of the anterior surface of the muscle from this aponeurosis muscular fibers arise and converge to another aponeurosis which covers the lower part of the posterior surface of the muscle and contracts into the tendon of insertion Insertion edit The semimembranosus muscle inserts on the medial condyle of the tibia 1 medial margin of the tibia 1 lateral condyle of femur 1 fascia of the popliteus muscle 1 The tendon of insertion gives off certain fibrous expansions one of considerable size passes upward and laterally to be inserted into the posterior lateral condyle of the femur forming part of the oblique popliteal ligament of the knee joint a second is continued downward to the fascia which covers the popliteus muscle while a few fibers join the medial collateral ligament of the joint and the fascia of the leg Nerve supply edit The semimembranosus is innervated by the tibial part of the sciatic nerve 1 The sciatic nerve consists of the anterior divisions of ventral nerve roots from L4 through S3 These nerve roots are part of the larger nerve network the sacral plexus 2 The tibial part of the sciatic nerve is also responsible for innervation of semitendinosus and the long head of biceps femoris Variation edit The semimembranosus muscle may be reduced or absent or double arising mainly from the sacrotuberous ligament and giving a slip to the femur or adductor magnus Function editThe semimembranosus muscle extends straightens the hip joint It also flexes bends the knee joint 1 It also helps to medially rotate the knee the tibia medially rotates on the femur when the knee is flexed It medially rotates the femur when the hip is extended The muscle can also aid in counteracting the forward bending at the hip joint 2 Clinical significance editThe semitendinosus muscle may be dry needled 1 Additional images edit nbsp Right hip bone External surface nbsp Bones of the right leg Posterior surface nbsp The popliteal posterior tibial and peroneal arteries nbsp Back of left lower extremity nbsp Semimembranosus muscle nbsp Semimembranosus muscle nbsp Muscles of thigh Lateral view nbsp Muscles of thigh Cross section nbsp Muscles of thigh Anterior views See also editThis article uses anatomical terminology Semitendinosus Biceps femorisReferences edit nbsp This article incorporates text in the public domain from page 479 of the 20th edition of Gray s Anatomy 1918 a b c d e f g h i Sandalcidi Dawn Dommerholt Jan 2013 01 01 Dommerholt Jan Fernandez de las Penas Cesar eds 10 Deep dry needling of the hip pelvis and thigh muscles Trigger Point Dry Needling Oxford Churchill Livingstone pp 133 150 doi 10 1016 b978 0 7020 4601 8 00010 4 ISBN 978 0 7020 4601 8 retrieved 2021 03 01 a b Saladin Kenneth S Anatomy amp Physiology the unity of form and function 5th ed New York McGraw Hill 2010 Print External links edit nbsp Wikimedia Commons has media related to Semimembranosus muscles Anatomy photo 14 st 0408 at the SUNY Downstate Medical Center Anatomy figure 14 01 07 at Human Anatomy Online SUNY Downstate Medical Center Muscles hamstrings of the posterior compartment of the thigh Anatomy figure 14 02 06 at Human Anatomy Online SUNY Downstate Medical Center Muscles that form the superficial boundaries of the popliteal fossa knee surface surface4 at the Dartmouth Medical School s Department of Anatomy PTCentral Portal nbsp Anatomy Retrieved from https en wikipedia org w index php title Semimembranosus muscle amp oldid 1211313428, wikipedia, wiki, book, books, library,

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