anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

, a joint capsule or articular capsule is an envelope surrounding a

synovial joint A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulat ...

.eMedicine/Stedman Medical Dictionary Lookup!
Each joint capsule has two parts: an outer fibrous layer or membrane, and an inner synovial layer or membrane.

Membranes

Each capsule consists of two layers or membranes: * an outer (fibrous membrane, ''fibrous stratum'') composed of avascular white fibrous tissue * an inner (''

synovial membrane The synovial membrane (also known as the synovial stratum, synovium or stratum synoviale) is a specialized connective tissue that lines the inner surface of capsules of synovial joints and tendon sheath A tendon sheath is a layer of synovial m ...

'', ''synovial stratum'') which is a secreting layer On the inside of the capsule, articular cartilage covers the end surfaces of the bones that articulate within that joint. The outer layer is highly innervated by the same nerves which perforate through the adjacent muscles associated with the joint.

Fibrous membrane

The fibrous membrane of the joint capsule is attached to the whole circumference of the articular end of each

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...

entering into the joint, and thus entirely surrounds the articulation. It is made up of dense connective tissue. It's a long spongy tissue.

Clinical significance

Frozen shoulder Adhesive capsulitis, also known as frozen shoulder, is a condition associated with shoulder pain and stiffness. It is a common shoulder ailment that is marked by pain and a loss of range of motion, particularly in external rotation. There is a l ...

(adhesive capsulitis) is a disorder in which the

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus