(Redirected from Sinew)
A 'tendon' (or 'sinew') is a tough band of
fibrous connective tissue that connects
muscle to
bone and is built to withstand
tension. Tendons are similar to
ligaments except that ligaments join one bone to another. Tendons and muscles work together and can only exert a pulling force.
Anatomy
The
origin of a tendon is where it joins to a muscle.
Collagen fibers from within the muscle organ are continuous with those of the tendon. A tendon inserts into bone at an
enthesis where the collagen fibers are mineralised and integrated into bone tissue. While they exert no pulling force of their own, tendons transfer the contractions of muscles and can exert an elastic force if forcibly stretched.
Tenocytes produce collagen molecules which aggregate end-to-end and side-to-side to produce collagen fibrils. Fibril bundles are organised by tenocytes to form fibres. Collagen fibres coalesce into macroaggregates. Groups of macroaggregates are bounded by connective tissue endotendon and are termed fascicles. Groups of fascicles are bounded by the epitendon and peritendon to form the tendon organ.
Blood vessels may be visualised within the endotendon running parallel to collagen fibres, with occasional branching transverse
anastomoses.
The internal tendon bulk is thought to contain no nerve fibres, but the epi- and peritendon contain nerve endings, while
Golgi tendon organs are present at the junction between tendon and muscle.
Tendon length varies in all major groups and from person to person. Tendon length is practically the discerning factor where muscle size and potential muscle size is concerned. For example, should all other relevant biological factors be 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. Cases in point: successful
bodybuilders will generally have short tendons and are said to have 'great genetics.' Examples of people with short tendons (in particular the upper arms) are
Casey Viator and
Arnold Schwarzenegger. Conversely, in sports requiring athletes to excel in actions such as running or jumping, it is beneficial to have longer than average
achilles tendon and a shorter calf muscle
[1] Some of the many professional athletes with long achilles tendons include
Allen Iverson,
Justin Gatlin and
Hicham El Guerrouj. Tendon length is determined by genes, and has not been shown to either increase or decrease in response to environment, unlike muscles which can be shortened by trauma, use imbalances and a lack of recovery and stretching.
Other information
Tendinitis refers to inflammation of a tendon.
The
Achilles tendon is a particularly large tendon connecting the
heel to the muscles of the
calf. It is so named because the mythic hero
Achilles was said to have been killed due to an injury to this area.
Sinew was also widely used in the medieval times as a form of ancient elastic. Some specific uses include using sinew as
thread for sewing, attaching feathers to arrows (see
fletch), lashing tool blades to shafts, etc. It also recommended in survival guides as a material from which strong ropes can be made for items like traps or living structures.
Tendon (particularly
beef tendon) is used as a food in some Asian cuisines (often served at
Yum Cha or
Dim Sum restaurants). One popular dish is Suan Bao Niu Jin, where the tendon is marinated in garlic.
See also
★
Aponeurosis
★
Chordae tendineae
★
Cartilage