Hamstring: Difference between revisions
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==Training== |
==Training== |
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In [[strength training]], the hamstrings are trained in isolation with the [[leg curl]] exercise, as well as a part of several other [[List of weight training exercises#Lower body|lower body exercises]]. |
In [[strength training]], the hamstrings are trained in isolation with the [[leg curl]] exercise, as well as a part of several other [[List of weight training exercises#Lower body|lower body exercises]]. |
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Hamstring plays an essential role in characterizing body [[Flexibility (anatomy)|flexibility]], which is assessed by performing a [[sit and reach]] test. Athlete's lower back and hamstring flexibility is defined by individual [[FlexiScore|flexibility score]]. |
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== See also == |
== See also == |
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Revision as of 02:50, 17 November 2010
| Hamstring | |
|---|---|
 Posterior view of left lower extremity. | |
| Details | |
| Origin | tuberosity of the ischium, linea aspera |
| Insertion | tibia, fibula |
| Artery | inferior gluteal artery, profunda femoris artery |
| Nerve | sciatic nerve (tibial nerve and common fibular nerve)[1][2] |
| Actions | flexion of knee |
| Antagonist | Rectus femoris muscle |
| Identifiers | |
| MeSH | D000070633 |
| Anatomical terms of muscle | |
In human anatomy, the hamstring refers to one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the posterior thigh muscles, or the tendons of the semitendinosus, the semimembranosus and the biceps femoris. In quadrupeds, it refers to the single large tendon found behind the knee or comparable area.
As shown in the diagram, the human hamstring occupies the posterior of the body of the femur.
Etymology
The word ham originally referred to the fat and muscle behind the knee. String refers to tendons, and thus, the hamstrings are the string-like tendons felt on either side of the back of the knee. Another commonly accepted origin is that legs of ham used to be hung by a hook through the space between the thighbone and the tendons behind the knee. Ham/pork used to be more common in England than beef and lamb.
The four muscles of the posterior thigh (semitendinosus, semimembranosus, biceps femoris long & short head) flex (bend) the knee, while three of the four extend (straighten) the hip. The three 'true' hamstrings cross both the hip and the knee joint and are therefore involved in knee flexion and hip extension. The short head of the biceps femoris crosses only one joint (knee) and is therefore not involved in hip extension. With its divergent origin and innervation it is sometimes excluded from the 'hamstring' characterization.[3]
| Muscle | Origin | Insertion | Nerve |
| semitendinosus | ischial tuberosity | medial surface of tibia | tibial |
| semimembranosus | ischial tuberosity | medial tibial condyle | tibial |
| biceps femoris - long head | ischial tuberosity | lateral side of the head of the fibula | tibial |
| biceps femoris - short head | lateral lip of the linea aspera near the head of the femur | lateral side of the head of the fibula (common tendon with the long head) | common fibular |
A portion of the adductor magnus is sometimes considered a part of the hamstrings.[3]
Functions
The hamstrings cross and act upon two joints - the hip and the knee.
Semitendinosus and semimembranosus extend the hip when the trunk is fixed; they also flex the knee and medially (inwardly) rotate the lower leg when the knee is bent.
The long head of the biceps femoris extends the hip as when beginning to walk; both short and long heads flex the knee and laterally (outwardly) rotates the lower leg when the knee is bent.
The hamstrings play a crucial role in many daily activities, such as, walking, running, jumping, and controlling some movement in the trunk. In walking, they are most important as an antagonist to the quadriceps in the deceleration of knee extension.
Injury
Straining of the hamstring, also known as a pulled hamstring, is defined as an excessive stretch or tear of muscle fibers and related tissues. Such injuries are very common in several sports and the common phrase "to be hamstrung" arises from this kind of injury and its potential to sideline an otherwise-healthy athlete.[citation needed] Hamstring injuries may result when an individual's training strengthens the quadriceps to the point where they become out of balance with the hamstrings, so that a powerful contraction from the quadriceps injures the hamstrings. These injuries can put athletes on the sidelines for two to six plus weeks depending on the severity of the injury.
Imaging
Imaging the hamstring muscles is usually performed with an ultrasound and/or MRI. [4] The biceps femoris is most commonly injured, followed by semitendinosus. Semimembranosus injury is rare. Imaging is useful in differentiating the grade of strain, especially if the muscle is completely torn.[5] In this setting, the level and degree of retraction can be determined, serving as a useful roadmap prior to any surgery. Those with a hamstring strain of greater than 60mm in length have a greater risk of recurrence.[6]
Use in surgery
The distal semitendinosus tendon is one of the tendons that can be used in the surgical procedure ACL reconstruction. In this procedure, a piece of it is used to replace the anterior cruciate ligament (ACL). The ACL is one of the four major ligaments in the knee.
Training
In strength training, the hamstrings are trained in isolation with the leg curl exercise, as well as a part of several other lower body exercises. Hamstring plays an essential role in characterizing body flexibility, which is assessed by performing a sit and reach test. Athlete's lower back and hamstring flexibility is defined by individual flexibility score.
See also
References
- ^ University of Glasgow :: Biomedical & Life Sciences :: Biomedical & Life Sciences
- ^ [1]
- ^ a b postthigh at The Anatomy Lesson by Wesley Norman (Georgetown University)
- ^ Koulouris G, Connell D. (2003). "Evaluation of the hamstring muscle complex following acute injury". Skeletal Radiol. 32 (10): 582–9. PMID 12942206.,
- ^ Schache AG, Koulouris G, Kofoed W, Morris HG, Pandy MG (2008). "Rupture of the conjoint tendon at the proximal musculotendinous junction of the biceps femoris long head: a case report". Knee Surg Sports Traumatol Arthrosc. 16 (8): 797–802. PMID 18360748.
{{cite journal}}: CS1 maint: multiple names: authors list (link), - ^ Koulouris G, Connell DA, Brukner P, Schneider-Kolsky M. (2007). "Magnetic resonance imaging parameters for assessing risk of recurrent hamstring injuries in elite athletes". Am J Sports Med. 35 (9): 1500–6. PMID 174262838.
{{cite journal}}: Check|pmid=value (help)CS1 maint: multiple names: authors list (link),
