List of subjects in Gray's Anatomy: IV. Myology

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

Tendonitis 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 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 fibre. 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 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 utilised sinew as the only cordage for all domestic purposes due to the lack of other suitable fibre sources in their ecological habitats.

List of subjects in Gray's Anatomy: IV. Myology

mechanics of muscle (Template:GraySubject)

development of the muscles (Template:GraySubject)

tendons, aponeuroses, and fasciae (Template:GraySubject)

Overview

Anatomy

Other information

See also

References

the fasciae and muscles of the head

the muscles of the scalp (Template:GraySubject)

the muscles of the eyelid (Template:GraySubject)

the muscles of the nose (Template:GraySubject)

the muscles of the mouth (Template:GraySubject)

the muscles of mastication (Template:GraySubject)

the fasciae and muscles of the anterolateral region of the neck

the superficial cervical muscle (Template:GraySubject)

the lateral cervical muscles (Template:GraySubject)

the supra- and infrahyoid muscles (Template:GraySubject)

the anterior vertebral muscles (Template:GraySubject)

the lateral vertebral muscles (Template:GraySubject)

the fasciae and muscles of the trunk

the deep muscles of the back (Template:GraySubject)

the suboccipital muscles (Template:GraySubject)

the muscles of the thorax (Template:GraySubject)

the muscles and fasciae of the abdomen (Template:GraySubject)

the anterolateral muscles

the posterior muscles

the muscles and fasciae of the pelvis (Template:GraySubject)

the muscles and fasciae of the perineum (Template:GraySubject)

The Muscles of the Anal Region

The Muscles of the Urogenital Region in the Male

The Muscles of the Urogenital Region in the Female

the fascia and muscles of the upper extremity

the muscles connecting the upper extremity to the vertebral column (Template:GraySubject)

the muscles connecting the upper extremity to the anterior and lateral thoracic walls (Template:GraySubject)

the muscles and fasciae of the shoulder (Template:GraySubject)

the muscles and fasciae of the arm (Template:GraySubject)

the muscles and fasciae of the forearm (Template:GraySubject)

The Volar Antibrachial Muscles: Superficial Group

The Volar Antibrachial Muscles: Deep Group

The Dorsal Antibrachial Muscles: Superficial group