Fasciae are collagen-rich layers of connective tissue that run through the entire body as a continuous network. They envelop individual muscle fibres (endomysium), muscle bundles (perimysium) and whole muscles (epimysium) and continue into tendons, ligaments and joint capsules.
Functionally, fasciae contribute to force transmission, shape and the gliding capacity between neighbouring structures. They also contain numerous nerve and receptor endings, which is why they are involved in proprioception and pain perception. Changes such as adhesions or reduced gliding capacity are discussed in physiotherapy.