Tendon 144865 226126979 2008-07-16T22:55:46Z GameKeeper 733794 /* References */ add Category:Tendons|* {{otheruses}} {{refimprove|date=August 2007}} {{Infobox Anatomy | Name = {{PAGENAME}} | Latin = tendo | GraySubject = | GrayPage = | Image = | Caption = | Image2 = | Caption2 = | Precursor = | System = | Artery = | Vein = | Nerve = | Lymph = | MeshName = | MeshNumber = | DorlandsPre = t_04 | DorlandsSuf = 12793900 | }} A '''tendon''' (or '''sinew''') is a tough band of [[fibrous connective tissue]] that usually connects [[muscle]] to [[bone]]<ref>[http://www.emedicine.com/asp/dictionary.asp?keyword=tendon eMedicine/Stedman Medical Dictionary Lookup!<!-- Bot generated title -->]</ref> and is capable of withstanding [[tension (physics)|tension]]. Tendons are similar to [[ligament]]s except that ligaments join one bone to another. Tendons and muscles work together and can only exert a pulling force. ==Structure== Normal healthy tendons are composed of parallel arrays of [[collagen]] fibers closely packed together. The fibers are mostly collagen type I, however there is also collagen type III and V present. These collagens are held together with other proteins, particularly the [[proteoglycan]], [[decorin]] and, in compressed regions of tendon, [[aggrecan]]. The [[tenocytes]] produce the collagen molecules which aggregate end-to-end and side-to-side to produce collagen fibrils. Fibril bundles are organized to form fibers with the elongated tenocytes closely packed between them. Collagen fibers 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 visualized within the endotendon running parallel to collagen fibers, with occasional branching transverse [[anastomosis|anastomoses]]. The internal tendon bulk is thought to contain no nerve fibers, 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. Successful [[Bodybuilding|bodybuilders]] will generally have shorter tendons. 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.<ref>{{cite web|title=Having a short Achilles tendon may be an athlete's Achilles heel|url=http://www.sportsinjurybulletin.com/archive/achilles-tendon.html| accessdate=2007-10-26}}</ref> Tendon length is determined by genetic predisposition, 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.{{Fact|date=June 2007}} ==Function== Tendons have been traditionally considered to simply be a mechanism by which muscles connect to bones, functioning simply to transmit forces. However, over the past two decades, much research has focused on the elastic properties of tendons and their ability to function as a spring. This allows tendons to passively modulate forces during locomotion, providing additional stability with no active work. It also allows tendons to store and recover energy at high efficiency. For example, during a human stride, the Achilles tendon stretches as the ankle joint dorsiflexes. During the last portion of the stride, as the foot plantar-flexes (pointing the toes down), the stored elastic energy is released. Furthermore, because the tendon stretches, the muscle is able to function with less or even [[muscle_contraction#Force-length_and_Force-velocity_Relationships|no change in length]], allowing the muscle to generate greater force. ==Pathology== [[Tendonitis]] refers to inflammation of a tendon. [[Tendinosis]] refers to non-inflammatory injury to the tendon at the cellular level. ==Other information== {{Trivia|date=June 2007}} The [[Achilles tendon]] is a particularly large tendon connecting the [[heel]] to the muscles of the [[calf muscle|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 throughout [[pre-industrial]] eras as a tough, durable [[fiber]]. Some specific uses include using sinew as [[yarn|thread]] for sewing, attaching feathers to arrows (see [[Fletch (archery)|fletch]]), lashing tool blades to shafts, etc. It also recommended in survival guides as a material from which strong cordage can be made for items like traps or living structures. Tendon must be treated in specific ways to function usefully for these purposes. [[Inuit]] and other [[circumpolar]] people utilized sinew as the only cordage for all domestic purposes due to the lack of other suitable fiber sources in their ecological habitats. The elastic properties of particular sinews were also used in [[composite bow|composite recurved bows]] favoured by the steppe nomads of Eurasia. The first stone throwing artillery also used the elastic properties of sinew. 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]] *[[Tendon sheath]] ==References== <references/> [[Category:Skeletal system]] [[Category:Tendons|*]] [[ceb:Tendon]] [[de:Sehne (Anatomie)]] [[es:Tendón]] [[eo:Tendeno]] [[fr:Tendon]] [[it:Tendine]] [[he:גיד]] [[nl:Pees (anatomie)]] [[ja:腱]] [[no:Sene]] [[pl:Ścięgna (anatomia)]] [[pt:Tendão]] [[qu:Anku]] [[ru:Сухожилие]] [[simple:Tendon]] [[sk:Šľacha]] [[fi:Jänne]] [[sv:Sena]] [[uk:Сухожилля]]