Hamstring

Hamstring

Infobox Muscle
Name = PAGENAME
Latin =
GraySubject = 128
GrayPage = 478


Caption = Back of left lower extremity.
Caption2 = Interior muscular view of the three muscles that make up the hamstring
Origin = tuberosity of the ischium, linea aspera
Insertion = tibia, fibula
Blood = inferior gluteal artery, profunda femoris artery
Nerve = sciatic nerve, tibial nerve [ [http://www.gla.ac.uk/ibls/fab/tutorial/anatomy/knee1.html University of Glasgow :: Biomedical & Life Sciences :: Biomedical & Life Sciences ] ]
Action = flexion of knee
Antagonist = Rectus femoris muscle
DorlandsPre = h_02
DorlandsSuf = 12407578
In human anatomy, a hamstring refers to one of the tendons that make 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. 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, the long muscle.

The three muscles of the posterior thigh (semitendinosus, semimembranosus, biceps femoris) flex (bend) the knee, while three of the four extend (straighten) the hip. The short head of the biceps femoris, with its divergent origin and innervation, is not involved in hip extension, and thus is sometimes excluded from the 'hamstring' characterization. [NormanAnatomy|postthigh]

A portion of the adductor magnus is sometimes considered a part of the hamstrings. [NormanAnatomy|postthigh]

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 or extend the trunk when the hip 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.

Injuries

Straining of the hamstring, also known as a pulled hamstring, is defined as an excessive stretch or tear of muscle fibers and related tissues.

Use in surgery

The distal semitendinosis 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.

See also

* Popliteal fossa
* Lombard's Paradox

References

External links

* [http://www.harkema.ucla.edu/hamstring.jpgIllustration at ucla.edu]
*


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  • hamstring — (v.) 1640s, to disable, render useless, a figurative verbal extension from the noun hamstring tendon at the back of the knee (1560s), from ham bend of the knee (see HAM (Cf. ham) (1)) + STRING (Cf. string). Cutting this would render a person or… …   Etymology dictionary

  • hamstring — [ham′striŋ΄] n. 1. one of the tendons at the back of the human knee 2. the large tendon at the back of the hock in a four legged animal 3. any of three large muscles that form the back of the thigh and work together to flex the leg, extend the… …   English World dictionary

  • Hamstring — Ham string (h[a^]m str[i^]ng ), n. (Anat.) One of the great tendons situated in each side of the ham, or space back of the knee, and connected with the muscles of the back of the thigh. [1913 Webster] …   The Collaborative International Dictionary of English

  • Hamstring — Ham string , v. t. [imp. & p. p. {Hamstrung}; p. pr. & vb. n. {Hamstringing}. See {String}.] To lame or disable by cutting the tendons of the ham or knee; to hough; hence, to cripple; to incapacitate; to disable. [1913 Webster] So have they… …   The Collaborative International Dictionary of English

  • hamstring — index deter, hinder, obstruct Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • hamstring — [v] disable cripple, debilitate, handicap, hinder, hobble, immobilize, impair, lame, maim, mangle, paralyze, weaken; concepts 130,246 …   New thesaurus

  • hamstring — ► NOUN 1) any of five tendons at the back of a person s knee. 2) the great tendon at the back of a quadruped s hock. ► VERB (past and past part. hamstrung) 1) cripple by cutting the hamstrings. 2) severely restrict; thwart. ORIGIN …   English terms dictionary

  • Hamstring — The prominent tendons at the back of the knee. They are the sidewalls of the hollow behind the knee. (This hollow is called the popliteal space). Both hamstrings connect to muscles that flex the knee. A pulled hamstring is a common athletic… …   Medical dictionary

  • hamstring — [[t]hæ̱mstrɪŋ[/t]] hamstrings, hamstringing, hamstrung 1) N COUNT A hamstring is a length of tissue or tendon behind your knee which joins the muscles of your thigh to the bones of your lower leg. Webster has not played since suffering a… …   English dictionary

  • hamstring — ham|string1 [ˈhæmˌstrıŋ] n a ↑tendon behind your knee, which sometimes gets injured when you do sport ▪ He pulled a hamstring in training. hamstring injury/problem/strain etc hamstring 2 hamstring2 past tense and past participle hamstrung [… …   Dictionary of contemporary English

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