German Contact How to study Login Register

Register now and grab your free ultimate anatomy study guide!

Sidebar ebook trimmed

Posterior Thigh Muscles



The upper part of the leg, or region between the hip joint and knee joint, is referred to as the thigh. The thigh is divided into three muscular compartments:

  • The anterior compartment
  • The medial compartment
  • The posterior compartment

The posterior compartment is separated from the anterior compartment by a lateral intermuscular septum. However, there is no septum separating the posterior compartment from the medial compartment. The posterior compartment comprises three muscles collectively known as the hamstrings. These include the:

  • Semimembranosus
  • Semitendinosus
  • Biceps femoris

This article will talk about the action of these muscles and their anatomical locations as well as their vascular supply and nerve innervation. Finally, it will go over the pathology of the hamstrings in a clinical setting.

Recommended video: Posterior thigh muscles
Origins, insertions, innervation and functions of the posterior thigh muscles.


The muscles of the posterior compartment cross both the hip and knee joints and thus have actions at both of these joints. The action of the hamstrings is to extend the thigh at the hip joint and flex the leg at the knee joint. When the knee is in the flexed position, the biceps femoris can externally rotate the leg whereas the semimembranosus and semitendinosus can act as internal rotators at the knee joint.



The semimembranosus is located medially in the posterior compartment, varies in size and has a flat, membranous shape. It originates from the lateral impression of the ischial tuberosity, by a long, flat tendon. The tendon descends deep to the long head of biceps femoris and to the semitendinosus muscle and forms an aponeurosis. At about midthigh, muscle fibres arise from this aponeurosis. The muscle then converges with another aponeurosis and then forms a rounded tendon. This tendon descends to attach to the horizontal concavity on the posterior aspect of the medial tibial condyle.

Semimembranosus muscle - dorsal view

Semimembranosus muscle - dorsal view


The semitendinosus is also situated posteriomedially in the thigh, but runs superficially to the semimembranosus. It arises from the medial impression of the ischial tuberosity by a shared tendon with the long head of the biceps femoris. A muscular belly arises from this tendon, which is fusiform in shape. A rounded tendon then arises just below midthigh. The great length of this tendon gives the muscle its name. It then crosses the medial collateral ligament before attaching to the upper part of the tibia medially, behind the tendon attachment of the gracilis.

Semitendinosus muscle - dorsal view

Semitendinosus muscle - dorsal view

Biceps Femoris

The biceps femoris is once again situated posteriomedially, however, it consists of two heads or proximal attachments. The long head of the biceps femoris arises from the medial impression of the ischial tuberosity through a shared tendon with the semitendinosus. The short head arises from the femur at the linea aspera and the lateral supracondylar ridge. The long head crosses the sciatic nerve before forming an aponeurosis. The short head joins with this aponeurosis on its deep surface. A tendon is formed from this aponeurosis distally and inserts into the head of the fibula.

Biceps femoris muscle - dorsal view

Biceps femoris muscle - dorsal view

Blood Supply

Semimembranosus - perforating arteries (predominantly the first), which branch from the profunda femoris artery. The muscle is also supplied by the inferior gluteal artery.

Semitendinosus - first perforating artery of the profunda femoris artery and the inferior gluteal artery.

Biceps Femoris - the long head is supplied by the first and second perforating arteries of the profunda femoris. The short head is supplied by the second or third perforating arteries of the profunda femoris. Both heads are also supplied by the inferior gluteal artery as well as muscular branches of the popliteal artery.


The nerve innervation of the hamstrings is by the tibial division of the sciatic nerve (L5-S2) except for the short head of the biceps femoris, which is supplied by the common fibular division of the sciatic nerve (L5-S2).

Sciatic nerve - ventral view

Sciatic nerve - ventral view

Clinical Notes


The power of the hamstrings is clinically tested by active flexion of the knee against resistance. The power of the individual hamstring tendons can be assessed more accurately whilst the subject is prone. A strain or tear of the hamstrings, sometimes known as a pulled or torn hamstring is a common sports injury in individuals who are required to start and stop often or run very hard e.g. in those who play basketball and football etc.


An avulsion or a tear may occur when an individual violently exerts a muscle. This commonly causes the proximal tendons to tear away from the ischial tuberosity, resulting in bruising (or a contusion), muscle fibre tears and blood vessel rupture which produces a haematoma. Tearing of the hamstring muscle fibres usually results in a sharp, intense pain. Stretching and adequate warming up help prevent this injury.

Get me the rest of this article for free
Create your account and you'll be able to see the rest of this article, plus videos and a quiz to help you memorize the information, all for free. You'll also get access to articles, videos, and quizzes about dozens of other anatomy systems.
Create your free account ➞
Show references


  • C.S. Sinnatamby, R.J. Last: Last’s Anatomy, 12th Edition, Elsevier/Churchill Livingstone (2006), p.135-6. 
  • S. Standring: Gray’s Anatomy The Anatomical Basis Of Clinical Practice, 40th Edition, Elsevier Health Sciences UK (2008), p. 1377-8. 
  • K.L. Moore, A.F. Dalley, A.M.R. Agur: Clinically Oriented Anatomy, 7th Edition, Wolters Kluwer/Lippincott Williams & Wilkins Health (2014), p. 581. 
  • G.J. Tortora, M.T. Nielsen: Principles Of Human Anatomy, 12th Edition, John Wiley (2012), p.421.

Author, Review and Layout:

  • Charlotte O'leary
  • Latitia Kench
  • Catarina Chaves


  • Semimembranosus muscle - dorsal view - Liene Znotina
  • Semitendinosus muscle - dorsal view - Liene Znotina
  • Biceps femoris muscle - dorsal view - Liene Znotina
  • Sciatic nerve - ventral view - Begoña Rodriguez
© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Continue your learning

Article (You are here)
Other articles
Well done!

Register now and grab your free ultimate anatomy study guide!

Sidebar ebook trimmed
Create your free account.
Start learning anatomy in less than 60 seconds.