Hamstring

Any of the three tendons in the thigh

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, extension of hip
Antagonist| Rectus femoris muscle
Identifiers
MeSH| D000070633
Anatomical terms of muscle

[edit on Wikidata]

In human anatomy, a hamstring (/ˈhæmstrɪŋ/) is any one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus, semitendinosus and biceps femoris).[3] The hamstrings are susceptible to injury.[4] In quadrupeds, the hamstring is the single large tendon found behind the knee or comparable area.

## Contents

* 1 Criteria
* 2 Structure
* 3 Function
* 4 Clinical significance
* 4.1 Sports running injuries
* 4.2 Imaging
* 4.3 Use in surgery
* 5 History
* 5.1 Etymology
* 6 See also
* 7 References
* 8 External links

## Criteria[edit]

The common criteria of any hamstring muscles are:

1. Muscles should originate from ischial tuberosity.
2. Muscles should be inserted over the knee joint, in the tibia or in the fibula.
3. Muscles will be innervated by the tibial branch of the sciatic nerve.
4. Muscle will participate in flexion of the knee joint and extension of the hip joint.

Those muscles which fulfill all of the four criteria are called true hamstrings.
The adductor magnus reaches only up to the adductor tubercle of the femur, but it is included amongst the hamstrings because the tibial collateral ligament of the knee joint morphologically is the degenerated tendon of this muscle. The ligament is attached to medial epicondyle, two millimeters from the adductor tubercle.

## Structure[edit]

The three muscles of the posterior thigh (semitendinosus, semimembranosus, biceps femoris long & short head) flex (bend) the knee, while all but the short head of biceps femoris 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.[5]

Muscle | Origin | Insertion | Nerve

|
|
|

semitendinosus | ischial tuberosity | medial surface of tibia | tibial part of sciatic
semimembranosus | ischial tuberosity | medial tibial condyle | tibial part of sciatic
biceps femoris \- long head | ischial tuberosity | lateral side of the head of the fibula | tibial part of sciatic
biceps femoris \- short head | linea aspera and lateral supracondylar line of femur | lateral side of the head of the fibula (common tendon with the long head) | common peroneal

A portion of the adductor magnus is sometimes considered a part of the hamstrings.[5]

## Function[edit]

The hamstrings cross and act upon two joints – the hip and the knee – and as such they are termed biarticular muscles.

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) rotate 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 gluteus. In walking, they are most important as an antagonist to the quadriceps in the deceleration of knee extension.

## Clinical significance[edit]

### Sports running injuries[edit]

A common running injury in several sports, excessive stretch of a hamstring results from extensive hip flexion while the knee is extended.[4][6] During sprinting, a hamstring injury may occur from excessive muscle strain during eccentric contraction late in the leg swing phase.[4][6] The overall incidence of a hamstring injury in sports and professional dancers is about two per 1000 hours of performance.[4] 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.[4]

### Imaging[edit]

Tear of the hamstrings muscles at the ischial tuberosity seen on MRI (coronal STIR). The arrowheads indicate the tuber and the retracted tendon stump. Significant bleeding around and into the muscles.

Picture of pulled hamstring showing location of hamstring.

Imaging the hamstring muscles is usually performed with an ultrasound and/or MRI.[7] 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.[8] 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.[9]

### Use in surgery[edit]

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, which also include the posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL).

## History[edit]

### Etymology[edit]

The word "ham" is derived from the Old English ham or hom meaning the hollow or bend of the knee, from a Germanic base where it meant "crooked". It gained the meaning of the leg of an animal around the 15th century.[10] String refers to tendons, and thus, the hamstrings are the string-like tendons felt on either side of the back of the knee.[11]

## See also[edit]

This article uses anatomical terminology.

* Hamstringing
* Hamstring curl
* Lombard's Paradox
* Popliteal fossa
* Pulled hamstring

## References[edit]

1. ^ "University of Glasgow - Schools - School of Life Sciences". www.gla.ac.uk.
2. ^ "Biceps Femoris - Short Head — Musculoskeletal Radiology — UW Radiology". Rad.washington.edu. Retrieved 2012-11-02.
3. ^ Mayo Clinic Staff (3 Oct 2015). "Hamstring injury". Mayo clinic. Retrieved 6 July 2016.
4. ^ a b c d e Danielsson, Adam; Horvath, Alexandra; Senorski, Carl; Alentorn-Geli, Eduard; Garrett, William E.; Cugat, Ramón; Samuelsson, Kristian; Hamrin Senorski, Eric (2020-09-29). "The mechanism of hamstring injuries – a systematic review". BMC Musculoskeletal Disorders. 21 (1): 641. doi:10.1186/s12891-020-03658-8. ISSN 1471-2474. PMC 7526261. PMID 32993700.
5. ^ a b postthigh at The Anatomy Lesson by Wesley Norman (Georgetown University)
6. ^ a b Kenneally‐Dabrowski, Claire J. B.; Brown, Nicholas A. T.; Lai, Adrian K. M.; Perriman, Diana; Spratford, Wayne; Serpell, Benjamin G. (2019-05-22). "Late swing or early stance? A narrative review of hamstring injury mechanisms during high‐speed running". Scandinavian Journal of Medicine and Science in Sports. 29 (8): 1083–1091. doi:10.1111/sms.13437. ISSN 0905-7188. PMID 31033024. S2CID 139106410.
7. ^ Koulouris G, Connell D (2003). "Evaluation of the hamstring muscle complex following acute injury". Skeletal Radiol. 32 (10): 582–9. doi:10.1007/s00256-003-0674-5. PMID 12942206. S2CID 23597752.
8. ^ 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. doi:10.1007/s00167-008-0517-y. PMID 18360748. S2CID 23953024.
9. ^ 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. doi:10.1177/0363546507301258. PMID 17426283. S2CID 174755.
10. ^ Brown, Lesley, ed. (2007). Shorter Oxford English Dictionary II (Sixth ed.). Oxford: Oxford University press. p. 3611.
11. ^ "Online Etymology Dictionary". Etymonline.com. Retrieved 2012-11-02.

## External links[edit]

* MRI Images demonstrating avulsion fracture of the hamstring muscle origin

* v
* t
* e

Muscles of the hip and human leg

Iliac region|

* Iliopsoas
* psoas major/psoas minor
* iliacus

Buttocks|

* Gluteal muscles
* maximus
* medius
* minimus
* tensor fasciae latae

lateral rotator group:|

* quadratus femoris
* inferior gemellus
* superior gemellus
* internal obturator
* external obturator
* piriformis

Thigh /
compartments|

| Anterior|

* sartorius
* quadriceps
* rectus femoris
* vastus lateralis
* vastus intermedius
* vastus medialis
* articularis genus

|

Posterior|

* hamstring
* biceps femoris
* semitendinosus
* semimembranosus

Medial|

* pectineus
* external obturator
* gracilis
* adductor
* longus
* brevis
* magnus
* minimus

Fascia|

* Femoral sheath
* Femoral canal
* Femoral ring
* Adductor canal
* Adductor hiatus
* Muscular lacuna

fascia lata|

*     * Iliotibial tract
* Lateral intermuscular septum of thigh
* Medial intermuscular septum of thigh
* Cribriform fascia

Leg/
compartments|

| Anterior|

* tibialis anterior
* extensor hallucis longus
* extensor digitorum longus
* fibularis (peroneus) tertius

|

Posterior|

| superficial|

* triceps surae
* gastrocnemius
* soleus
* accessory soleus
* Achilles tendon
* plantaris

|

deep|

* tarsal tunnel
* flexor hallucis longus
* flexor digitorum longus
* tibialis posterior
* popliteus

Lateral|

* Fibularis (peroneus) muscles
* longus
* brevis

Fascia|

* Pes anserinus

Intermuscular septa|

* anterior
* posterior
* transverse

Foot|

| Dorsal|

* extensor hallucis brevis
* extensor digitorum brevis

|

Plantar|

* 1st layer
* abductor hallucis
* flexor digitorum brevis
* abductor digiti minimi
* 2nd layer
* quadratus plantae
* lumbrical muscle
* 3rd layer
* flexor hallucis brevis
* adductor hallucis
* flexor digiti minimi brevis
* 4th layer
* dorsal interossei
* plantar interossei

Fascia|

* Plantar fascia
* retinacula
* Peroneal
* Inferior extensor
* Superior extensor
* Flexor

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