anatomy Anatomy () is the branch of morphology concerned with the study of the internal 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 scien ...

, 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' articulati ...

.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 Synovial () may refer to: * Synovial fluid * 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 bou ...

'', ''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, ...

entering into the joint, and thus entirely surrounds the articulation. It is made up of

dense connective tissue Dense connective tissue, also called dense fibrous tissue, is a type of connective tissue with fibers as its main extracellular matrix, matrix element. The fibers are mainly composed of type I collagen. Crowded between the collagen fibers are rows ...

. It's a long spongy tissue.

Clinical significance

Frozen shoulder (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 (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder m ...

capsule becomes inflamed. Plica syndrome is a disorder in which the synovial plica becomes inflamed and causes abnormal biomechanics in the knee.

Gallery

File:Gray201.png, Left clavicle. Inferior surface. File:Gray235.png, Right hip bone. External surface. File:Slide2bib.JPG, Right knee in extension. Deep dissection. Posterior view. File:Slide2cocc.JPG, Right knee in extension. Deep dissection. Posterior view.

References

External links