The human body includes more than 640 muscles, the sizes of which vary according to their function. On average, these muscles constitute 40% of the dry weight of the body.
Striated muscles and smooth muscles can be distinguished:
Striated (striped) muscles are under the control of the central nervous system. They generally unite bones with each other (skeletal  muscles): they allow movement.
Smooth muscles are under the control of the autonomous nervous system: for example, the stomach has two layers of smooth muscle tissue.

 With regard to injuries, there are two types: soft tissues and bones.
Injuries involving the soft tissues affect the muscles and ligaments, whereas injuries involving the bones are generally more serious: fractures, dislocations, etc. Specific medical treatment is required for them.

Soft tissue injuries may be represented by bruises (small blood vessels are damaged and bleed into the tissues), muscle tears (torn muscle fibres) or ligament damage (torn ligamental tissues).

Advice for the management of soft tissues injuries such as muscle pain, muscle soreness or minor bruises: R.I.C.E.R (Rest; Ice; Compression; Elevation; Referral).