Hamstrings

They are so called because in pigs they are the muscles used to make ham, and the hams were strung up using hooks through the long string-like tendons.

The hamstrings are in fact three individual muscles:

• semi-tendinosus
• semi-membranosus
• biceps femoris

The hamstrings muscles contract to flex (bend) the knee and extend (straighten) the hip. Tight hamstrings often make a sportsperson prone to injury, or a knee patient prone to re-injury and hamstrings stretches are an important part of knee rehabilitation.

You can feel the hamstrings tendons on either side at the back of the knee. Those on the medial (inner) aspect are the semi-tendinosus and semi-membranosus. On the lateral (outer) aspect is the biceps femoris.

Hamstrings graft for torn cruciates

The stringy semi-tendinosus tendon inserts at the top end of the tibia, together with two other stringy tendons of two other muscles - sartorius and gracilis. Where these three attach to the bone they are joined in a web-like structure resembling a goose foot, and hence these three tendons (one of which is a hamstrings) are also called the 'goose-foot' or pes anserine tendons. The importance of this is that semi-tendinosus and gracilis tendons can be stripped up ('harvested') from their bony attachment and used to replace the cruciate ligament.