Joint capsule

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 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.

The fibrous membrane of the joint capsule is attached to the whole circumference of the articular end of each bone entering into the joint, and thus entirely surrounds the articulation. It is made up of dense connective tissue. It's a long spongy tissue.

Frozen shoulder (adhesive capsulitis) is a disorder in which the shoulder capsule becomes inflamed.

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

• 
  Left clavicle. Inferior surface.
• 
  Right hip bone. External surface.
• 
  Right knee in extension. Deep dissection. Posterior view.
• 
  Right knee in extension. Deep dissection. Posterior view.

• Articular capsule of the humerus
• Articular capsule of the knee joint
• Atlanto-axial joint
• Capsule of atlantooccipital articulation
• Capsule of hip joint
• Capsule of temporomandibular joint

This article incorporates text in the public domain from page 282 of the 20th edition of Gray's Anatomy (1918)

• Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna