semimembranosus muscle

Information about semimembranosus muscle

Semimembranosus muscle
Muscles of the gluteal and posterior femoral regions. Semimembranosus labeled at bottom left.
Semimembranosus labeled at bottom right.
Latinmusculus semimembranosus
subject #128 479
Origin:Ischial tuberosity
Insertion:Medial surface of tibia
Artery:profunda femoris, gluteal artery
Nerve:sciatic nerve
Action:Hip extension, Knee flexion
Antagonist:Quadriceps muscle
Dorlands/Elsevier m_22/12550673
The semimembranosus is a muscle in the back of the thigh. It is the most medial of the three hamstring muscles.

Structure

The semimembranosus, so called from its membranous tendon of origin, is situated at the back and medial side of the thigh.

It arises by a thick tendon from the upper and outer impression on the tuberosity of the ischium, above and lateral to the biceps femoris and semitendinosus.

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.

It is inserted mainly into the horizontal groove on the posterior medial aspect of the medial condyle of the tibia.

The tendon of insertion gives off certain fibrous expansions: one, of considerable size, passes upward and lateralward to be inserted into the back part of the 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 tibial collateral ligament of the joint and the fascia of the leg.

The muscle overlaps the upper part of the popliteal vessels.

Innervation

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

Actions

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

Variations

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

Additional images


Right hip bone. External surface.

Bones of the right leg. Posterior surface.

The popliteal, posterior tibial, and peroneal arteries.

Back of left lower extremity.


See also

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.
 •  • [ e]
Muscles of lower limbs
ILIAC REGION/ILIOPSOASpsoas major - psoas minor - iliacus
BUTTOCKSgluteals: (maximus, medius, minimus) - tensor fasciae latae
lateral rotator group: piriformis - obturator externus - obturator internus - inferior gemellus - superior gemellus - quadratus femoris
THIGHanterior compartment: sartorius - quadriceps (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) - articularis genu
medial compartment/adductor: gracilis - pectineus - adductor brevis - adductor longus - adductor magnus
posterior compartment/hamstring: biceps femoris - semitendinosus, semimembranosus
LEGanterior compartment: tibialis anterior - extensor hallucis longus - extensor digitorum longus - fibularis tertius
posterior compartment: superficial - calf/triceps surae (gastrocnemius, soleus) - plantaris deep - popliteus - tarsal tunnel (flexor hallucis longus - flexor digitorum longus - tibialis posterior)
lateral compartment: fibularis muscles (longus - brevis)
FOOTdorsal - 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
Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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bold refer to the diagram at right.)

In the skull (8):
  • 1-9. cranium
  • 7. mandible
''In the middle ears (6):
  • malleus
  • incus
  • stapes
In the throat (1):
  • hyoid
In the shoulder girdle (4):
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tuberosity of the ischium (or ischial tuberosity).

It marks the lateral boundary of the pelvic outlet.

When sitting, the weight is frequently placed upon the ischial tuberosity.
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bold refer to the diagram at right.)

In the skull (8):
  • 1-9. cranium
  • 7. mandible
''In the middle ears (6):
  • malleus
  • incus
  • stapes
In the throat (1):
  • hyoid
In the shoulder girdle (4):
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tibia is the larger of the two bones in the leg below the knee in vertebrates.

In humans

The tibia or shin bone, in human anatomy, is found medial (towards the middle) and anterior (towards the front) to the other such bone, the fibula.
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Arteries are muscular blood vessels that carry blood away from the heart.[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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The profunda femoris artery (also known as the deep femoral artery, or the deep artery of the thigh) is a branch of the femoral artery that, as its name suggests, travels more deeply (posteriorly) than the rest of the femoral artery.
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Gluteal artery can refer to:
  • Superior gluteal artery
  • Inferior gluteal artery

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  • Accessory nerve
  • Accessory obturator nerve
  • Alderman's nerve
  • Anococcygeal nerve
  • Ansa cervicalis
  • Anterior interosseous nerve
  • Anterior superior alveolar nerve
  • Aortic plexus
  • Auerbach's plexus
  • Auriculotemporal nerve
  • Axillary nerve

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The sciatic nerve (also known as the ischiatic nerve) is a large nerve that starts in the lower back and runs through the buttock and down the lower limb. It is the longest single nerve in the body.
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Kinesiology is the scientific study of the anatomy, physiology, and mechanics of body movement, especially in humans. [1] The word kinesiology is derived the Greek "kinesis" (motion) + the suffix -ology or -logy from the greek "logos" or "logia"(meaning a field of study).
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hip is the bony projection of the femur which is known as the greater trochanter, and the overlying muscle and fat. The hip joint is the joint between the femur and acetabulum of the pelvis and its primary function is to support the weight of the body in both static
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Extension is a movement of a joint. For example, extension is produced by extending the flexed elbow. The arm is now straight; it has been extended. If the head is tilted all the way back, it is said to be extended.

The movement in the opposite directions is called flexion.
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In human anatomy, the knee is the lower extremity joint connecting the femur and the tibia. Since in humans the knee supports nearly the entire weight of the body, it is the joint most vulnerable both to acute injury and to the development of osteoarthritis.
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flexion is a position that is made possible by the joint angle decreasing. The skeletal (bones, cartilage, and ligaments) and muscular (muscles and tendons) systems work together to move the joint into a "flexed" position.
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An antagonist is a kind of muscle that acts in opposition to the movement generated by the agonist and is responsible for returning a limb to its initial position.

Antagonistic pairs in houses

These antagonistic muscles are found in pairs called antagonistic pairs.
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"Quads" redirects here. For other uses see Quad
The quadriceps femoris (quadriceps, quadriceps extensor, guads or quads) includes the four prevailing muscles on the front of the thigh.
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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MUSCLE (multiple sequence comparison by log-expectation) is public domain, multiple sequence alignment software for protein and nucleotide sequences.
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In humans the thigh is the area between the pelvis and buttocks and the knee. Anatomically, it is part of the lower limb.

The single bone in the thigh is called the femur.
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In human anatomy, a hamstring refers to one of the tendons that makes up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the tendons of the semitendinosus, the semimembranosus, and the biceps femoris.
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In humans the thigh is the area between the pelvis and buttocks and the knee. Anatomically, it is part of the lower limb.

The single bone in the thigh is called the femur.
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The biceps femoris is a muscle of the posterior thigh. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group.

Origin and insertion

It has two heads of origin;
  • one, the long head

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

Structure

The semitendinosus, remarkable for the great length of its tendon of insertion, is situated at the posterior and medial aspect of the thigh.
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Aponeuroses (απο, "away" or "of", and νευρον, "sinew") are membranes separating muscles from each other. They have a shiny, whitish-silvery color, and are histologically similar to tendons, but are very sparingly supplied with blood
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tibia is the larger of the two bones in the leg below the knee in vertebrates.

In humans

The tibia or shin bone, in human anatomy, is found medial (towards the middle) and anterior (towards the front) to the other such bone, the fibula.
..... Click the link for more information.
In human anatomy, the knee is the lower extremity joint connecting the femur and the tibia. Since in humans the knee supports nearly the entire weight of the body, it is the joint most vulnerable both to acute injury and to the development of osteoarthritis.
..... Click the link for more information.
The popliteus muscle in the leg is used to unlock the knee by laterally rotating the femur on the tibia during a closed chain movement (such as one with the foot in contact with the ground).
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The sciatic nerve (also known as the ischiatic nerve) is a large nerve that starts in the lower back and runs through the buttock and down the lower limb. It is the longest single nerve in the body.
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In human anatomy, the knee is the lower extremity joint connecting the femur and the tibia. Since in humans the knee supports nearly the entire weight of the body, it is the joint most vulnerable both to acute injury and to the development of osteoarthritis.
..... Click the link for more information.

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