The Achilles tendon. The Achilles tendon is the strongest and thickest tendon in the body. The achilles is the most commonly injured tendon.


A tendon (= sinew) is a tough band of fibrous connective tissue that usually connects muscle to bone.

Tendons are white, glistening, fibrous cords, varying in length and thickness, sometimes round, sometimes flattened, and devoid of elasticity. They consist almost entirely of white fibrous tissue, the fibrils of which have an undulating course parallel with each other and are firmly united together. When boiled in water tendon is almost completely converted into gelatin, the white fibers being composed of the albuminoid collagen, which is often regarded as the anhydride of gelatin. They are very sparingly supplied with bloodvessels, the smaller tendons presenting in their interior no trace of them. [1]


1   Function


The primary function of the kneecap is knee extension. The patella increases the leverage that the tendon can exert on the femur.

Tendons have been traditionally considered to simply be a mechanism by which muscles connect to bone, functioning simply to transmit forces. This connection allows tendons to passively modulate forces during locomotion, providing additional stability with no active work.

Not all tendons are required to perform the same functional role, with some predominantly positioning limbs, such as the fingers when writing (positional tendons) and others acting as springs to make locomotion more efficient (energy storing tendons).

2   Substance

Tendons consist of dense regular connective tissue fascicles encased in dense irregular connective tissue sheaths. Normal healthy tendons are composed mostly of parallel arrays of collagen fibers closely packed together.

Tendon length varies in all major groups and from person to person. Tendon length is, in practice, the deciding factor regarding actual and potential muscle size. For example, all other relevant biological factors being equal, a man with a shorter tendons and a longer biceps muscle will have greater potential for muscle mass than a man with a longer tendon and a shorter muscle. Successful bodybuilders will generally have shorter tendons.

3   References

[1]Henry Gray. Anatomy of the Human Body: Myology. http://www.bartleby.com/107/102.html