The Info List - Hamstring

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


1 Criteria 2 Structure 3 Function 4 Clinical significance

4.1 Imaging 4.2 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:

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

Those muscle which fulfills 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.[4]

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.[4] Function[edit] 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) 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 trunk. In walking, they are most important as an antagonist to the quadriceps in the deceleration of knee extension. Clinical significance[edit] 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.

Imaging the hamstring muscles is usually performed with an ultrasound and/or MRI.[5]  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.[6] 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.[7] 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. 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.[8] String refers to tendons, and thus, the hamstrings are the string-like tendons felt on either side of the back of the knee.[9] See also[edit] This article uses anatomical terminology; for an overview, see Anatomical terminology.

Hamstringing Hamstring
curl Lombard's Paradox Popliteal fossa Pulled hamstring


^ "University of Glasgow - Schools - School of Life Sciences". www.gla.ac.uk.  ^ "Biceps Femoris - Short Head — Musculoskeletal Radiology — UW Radiology". Rad.washington.edu. Retrieved 2012-11-02.  ^ Mayo Clinic Staff (3 Oct 2015). " Hamstring
injury". Mayo clinic. Retrieved 6 July 2016.  ^ 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. doi:10.1007/s00256-003-0674-5. 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. doi:10.1007/s00167-008-0517-y. PMID 18360748.  ^ 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.  ^ Brown, Lesley, ed. (2007). Shorter Oxford English Dictionary II (Sixth ed.). Oxford: Oxford University press. p. 3611. ^ "Online Etymology Dictionary". Etymonline.com. Retrieved 2012-11-02. 

External links[edit]

Images demonstrating avulsion fracture of the hamstring muscle origin

v t e

of the hip and human leg

Iliac region


psoas major/psoas minor iliacus


Gluteal muscles

maximus medius minimus

tensor fasciae latae

lateral rotator group:

quadratus femoris inferior gemellus superior gemellus internal obturator external obturator piriformis

/ compartments


sartorius quadriceps

rectus femoris vastus lateralis vastus intermedius vastus medialis

articularis genus



biceps femoris semitendinosus semimembranosus


pectineus external obturator gracilis adductor

longus brevis magnus minimus


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


tibialis anterior extensor hallucis longus extensor digitorum longus peroneus tertius



triceps surae

gastrocnemius soleus accessory soleus Achilles tendon



tarsal tunnel

flexor hallucis longus flexor digitorum longus tibialis posterior



peroneus muscles

longus brevis


Pes anserinus

Intermuscular septa

anterior posterior transverse



extensor hallucis brevis extensor digitorum brevis


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


Plantar fascia retinacula

Peroneal Inferior extensor Superior ext