Editing Hamstring (section)

==Clinical significance==
===Sports running injuries===
A common running injury in several sports, excessive stretch of a hamstring results from extensive [[hip flexion]] while the knee is extended.<ref name=daniel/><ref name="Kenn">{{cite journal | last1=Kenneally-Dabrowski | first1=Claire J. B. | last2=Brown | first2=Nicholas A. T. | last3=Lai | first3=Adrian K. M. | last4=Perriman | first4=Diana | last5=Spratford | first5=Wayne | last6=Serpell | first6=Benjamin G. | title=Late swing or early stance? A narrative review of hamstring injury mechanisms during high-speed running | journal=Scandinavian Journal of Medicine and Science in Sports | volume=29 | issue=8 | date=2019-05-22 | issn=0905-7188 | pmid=31033024 | doi=10.1111/sms.13437 | pages=1083–1091| s2cid=139106410 }}</ref> During [[sprinting]], a hamstring injury may occur from excessive muscle strain during [[eccentric contraction]] late in the leg swing phase.<ref name=daniel/><ref name=Kenn/> The overall incidence of a hamstring injury in sports and professional dancers is about two per 1000 hours of performance.<ref name=daniel/> In some sports, a hamstring injury occurs at the incidence of 19% of all sports injuries, and results in an average time loss from competition of 24  days.<ref name=daniel/>

===Imaging===
[[File:Hamstring tear STIR cor annotatios.jpg|thumb|Tear of the hamstrings muscles at the ischial tuberosity seen on MRI (visible on a coronal [[Short tau inversion recovery|STIR]] MRI sequence). The arrowheads indicate the tuber{{which|reason=Upper or lower arrowhead?|date=November 2024}} and the retracted tendon stump.{{which|reason=Upper or lower arrowhead?|date=November 2024}} Significant bleeding around and into the muscles.]]
[[File:Pulled Hamstring.png|thumb|Picture of pulled hamstring showing location of hamstring]]

Imaging the hamstring muscles is usually performed with an [[ultrasound]] and/or [[MRI]].<ref name="pmid12942206">{{cite journal |vauthors=Koulouris G, Connell D |title=Evaluation of the hamstring muscle complex following acute injury|journal=Skeletal Radiol.|volume=32 |issue=10 |pages=582–9 |year=2003 |pmid=12942206 |doi=10.1007/s00256-003-0674-5|s2cid=23597752}}</ref> &nbsp;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.<ref name="pmid18360748">{{cite journal |vauthors=Schache AG, Koulouris G, Kofoed W, Morris HG, Pandy MG |title=Rupture of the conjoint tendon at the proximal musculotendinous junction of the biceps femoris long head: a case report.|journal=Knee Surg Sports Traumatol Arthrosc|volume=16 |issue=8 |pages=797–802 |year=2008 |pmid=18360748 |doi=10.1007/s00167-008-0517-y|s2cid=23953024}}</ref> 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 {{cvt|60|mm|in}} in length have a greater risk of recurrence.<ref name="pmid17426283">{{cite journal |vauthors=Koulouris G, Connell DA, Brukner P, Schneider-Kolsky M |title=Magnetic resonance imaging parameters for assessing risk of recurrent hamstring injuries in elite athletes.|journal=Am J Sports Med|volume=35 |issue=9 |pages=1500–6 |year=2007 |pmid=17426283 |doi=10.1177/0363546507301258|s2cid=174755}}</ref>

===Use in surgery===
The [[Anatomical terms of location#Proximal and distal|distal]] semitendinosus tendon is one of the tendons that can be used in the [[surgery|surgical procedure]] [[anterior cruciate ligament reconstruction|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, which also include the [[posterior cruciate ligament]] (PCL), [[medial collateral ligament]] (MCL), and [[fibular collateral ligament|lateral collateral ligament]] (LCL).