Tendon also have a role in the tensile properties of tendon. The structure of tendon is effectively a fibre composite material, built as a series of hierarchical levels. At each level of the hierarchy, the collagen units are bound together by either collagen crosslinks, or the proteoglycans, to create a structure highly resistant to tensile load. The elongation and the strain of the collagen fibrils alone have been shown to be much lower than the total elongation and strain of the entire tendon under the same amount of stress, demonstrating that the proteoglycan-rich matrix must also undergo deformation, and stiffening of
Achilles tendon of re-rupture is about 25% with casting. If appropriate treatment does not occur within 4 weeks of the injury outcomes are not as good. Tendon xanthomas are cholesterol deposits that commonly develop in the Achilles tendon of people with lipid metabolism disorders such as familial hypercholesterolemia. The Achilles' tendon is often tested as part of a neurological examination. In this examination, the tendon is hit with a tendon hammer. This tests the S1 and S2 spinal nerves: a normal response is plantar flexion (downward movement) of the foot. Apart from humans, the Achilles tendon is short or absent in great