Articular Capsule of Acromioclavicular Joint
Capsula articularis articulationis acromioclavicularis
Read moreAnatomical Relations
The articular capsule of the acromioclavicular joint completely surrounds the articular margins of the acromion of the scapula and the clavicle. The capsule is weak, and is strengthened by the acromioclavicular ligament superiorly, and to a lesser extent, inferiorly. Additionally, its fibers are intermingled with that of the aponeuroses of the trapezius and deltoid muscles for added strength.
Structure
The articular capsule of the acromioclavicular joint is a sac-like structure that enclosed the acromioclavicular joint. It is composed of two layers. The external layer, the fibrous membrane, is composed of dense fibrous tissue. The internal layer, the synovial membrane, lines the joint cavity and is composed of loose connective tissue.
Function
The articular capsule of the acromioclavicular joint ensures that the joint is sealed, thus, keeping the lubricating synovial fluid within the joint. It provides passive stability to the joint by limiting the joint movement. Additionally, it provides active stability by containing numerous proprioceptive nerve endings which relay mechanical information back to the central nervous system (Ralphs and Benjamin, 1994).
References
Ralphs, J. R. and Benjamin, M. (1994) 'The joint capsule: structure, composition, ageing and disease', Journal of Anatomy, 184(Pt 3), pp. 503-509.
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Joint Ligament
Entheseal structures are widely located throughout the body and are represented by the interface between bone and several tissues including tendon, joint capsules and ligaments.
