The cord of tissue that attaches the end of a muscle to bone or other structure upon which the muscle acts when it contracts. Tendons are composed of bundles of white fibrous tissue arranged in a very dense manner, and are very strong. Most tendons are surrounded by sheaths lined with membrane similar to the SYNOVIAL MEMBRANE lining joint-cavities: in this sheath the tendon glides smoothly over surrounding parts. The fibres of a tendon pass into the substance of the bone and blend with the fibres composing it. One of the largest tendons in the body is the Achilles tendon, or tendo calcaneus, which attaches the muscle of the calf to the calcaneus or heel-bone.
are one of the hazards of sports (see SPORTS MEDICINE). They usually result from indirect violence, or overuse, rather than direct violence.
usually results from the sudden application of an unbalanced load. Thus, complete rupture of the Achilles tendon is common in taking an awkward step backwards playing squash. There is sudden pain; the victim is often under the impression that he or she has received a blow. This is accompanied by loss of function, and a gap may be felt in the tendon.
is also accompanied by pain, but there is no breach of continuity or complete loss of function. Treatment of a complete rupture usually means surgical repair followed by immobilisation of the tendon in plaster of Paris for six weeks. Partial rupture usually responds to physiotherapy and immobilisation, but healing is slow.