Like ligaments, aponeuroses, and tendons, fasciae are dense regular connective tissues, containing closely packed bundles of collagen fibers oriented in a wavy pattern parallel to the direction of pull. Fasciae are consequently flexible structures able to resist great unidirectional tension forces until the wavy pattern of fibers has been straightened out by the pulling force. These collagen fibers are produced by the fibroblasts located within the fascia.
Fasciae are similar to ligaments and tendons as they have collagen as their major component. They differ in their location and function: ligaments join one bone to another bone, tendons join muscle to bone and fasciae surround muscles or other structures.
Fasciae are normally thought of as passive structures that transmit mechanical tension generated by muscular activities or external forces throughout the body.
The function of muscle fasciae is to reduce friction of muscular force. In doing so, fasciae provide a supportive and movable wrapping for nerves and blood vessels as they pass through and between muscles.
Fascia becomes important clinically when it loses stiffness, becomes too stiff or has decreased shearing ability. When inflammation or trauma causes fibrosis and adhesions, fascial tissue fails to differentiate the adjacent structures effectively. This can happen after surgery where the fascia has been incised and healing includes a scar that traverses the surrounding structures. A fasciotomy may be used to relieve compartment syndrome as a result of high pressure within an anatomical compartment created by fascia.