The muscles



Skeletal muscles exist as individual organs and act independently of each other within the body. Most skeletal muscles have an origin and an insertion. The origin being the end of the muscle which remains in relatively fixed position when the muscle contracts, and the insertion being the end which experiences more movement when a muscle contracts.

Dense regular connective tissues serve to connect the ends (origin and insertion) to the skeleton. The skeletal muscle fibers between the fixed ends of the muscle make up the belly of the muscle. Sometimes the muscle is attached to the skelton via a tendon (narrowed strap of connective tissue) or an aponeurosis (broad sheet of connective tissue). In other locations the muscles may be attached to other muscles by raphes (connective tissues joining muscles side by side) or by tendinous inscriptions (connective tissues joining muscles end to end).

A cross sectional view of the belly of a large skelatal muscle will show that the skeletal muscle fibers are aggregated in groups separated by connective tissues. There is also a layer of connective tissues surrounding the belly of the muscle, the epimysium. The bundles of muslce fibers within the belly of a muscle are called fasicles. These fasicles are also separated from each other by a dense connective tissue layer, the perimysium. Within each fasicle the individual skeletal muscle fibers are separated from each other by a mesh of loose connective tissues, the endomysium.









Skeletal muscle

Cardiac muscle

Smooth muscle

Anatomy of a skeletal muscle

Branchial and extrinsic eye muscles

Hypobrachial muscles

Body trunk muscles

Appendicular muscles

Special skeletal muscles