A tendon is a glistening white cord of connective tissue that attaches muscle to bone. It is similar in structure to ligament, which connects bone to bone.
Tendons play a critical role in the movement of the human body by transmitting the force created by muscles to move bones. In this was, they allow muscles to control movement from a distance. The fingers, for example, are moved by tendons with force supplied by the forearm muscles.
Like rope, tendons are tough, fibrous and flexible. They are not, however, particularly elastic. If they where, much of the muscular force tendons are intended to carry would have dissipated before it had a hence to reach, let alone move, the bones.
Tendons are formed from the same components that make up other kinds of connective tissue, such as cartilage, ligaments and bones. These components are collagen fibers, ground structures, and cells, which in the tendon are called fibrocytes. At the point where a tendon touches bone, the tendon fibers gradually pass into the substance of the bone and meld with it.
Some tendons run inside a fibrous sheath. Between the sheath and the tendon is a thin film of lubricant called synovial fluid. This arrangement helps tendons glide smoothly over surrounding parts.
What is Tenndonitis?
Inflammation of the tendon sheath is a painful condition known as tenosynovitis. Strain or trauma to a tendon sheath through repeated use, calcium deposits and high cholesterol levels are all potential causes. So too are diseases such as rheumatoid arthritis, relapsing polychondritis, gout or gonorrhea. Sometimes, during movement, a crackling noise occurs around the area of an inflamed tendon sheath.
Inflammation of a tendon itself leads to a condition known as tendinitis. It is most commonly caused by overuse or a sudden overstretching of a tendon. Both situations can lead to small tears or ruptures in a tendon. As tendons undergo a gradual process of degeneration with age, they weaken as people get older and become more prone to tendonitis.
