A Fibrous capsule can either mean the outer stratum encircling the entire perimeter of articular capsule of the synovial joint or a flexible, outer membrane enclosing the liver and kidneys. In general, this structure gives the anatomical structure it covers support and protection.

In synovial joints, fibrous capsule, being fixed to the bones and ligaments sustains the strength and stability of the whole composition while restricting undue motions.

On the other hand, visceral organs are sheltered against infection and injury. This collagenous shell of connective tissues which surrounds the outer hepatic surface is known as Glisson’s capsule. This sheath is also contained within a sole stratum of mesothelial cells. Kidneys too are also closely contained inside a strong capsule. With these structures in place, human beings can be greatly active without the fear of exposing organs to external physical forces.