The subacromial bursa is the synovial cavity located just below the
acromion
In human anatomy, the acromion (from Greek: ''akros'', "highest", ''ōmos'', "shoulder", plural: acromia) is a bony process on the scapula (shoulder blade). Together with the coracoid process it extends laterally over the shoulder joint. The acro ...
, which communicates with the
subdeltoid bursa in most individuals, forming the so-called subacromial-subdeltoid bursa (SSB).
The SSB bursa is located deep to the
deltoid muscle
The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up o ...
and the coracoacromial arch and extends laterally beyond the humeral attachment of the
rotator cuff
The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspi ...
, anteriorly to overlie the
intertubercular groove
The bicipital groove (intertubercular groove, sulcus intertubercularis) is a deep groove on the humerus that separates the greater tubercle from the lesser tubercle. It allows for the long tendon of the biceps brachii muscle to pass.
Structure ...
, medially to the
acromioclavicular joint
The acromioclavicular joint, or AC joint, is a joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. It is a plane synovial joint.
Structure ...
, and posteriorly over the rotator cuff. The SSB decreases
friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative lateral motion of t ...
, and allows free motion of the rotator cuff relative to the coracoacromial arch and the deltoid muscle.
French anatomist and surgeon
Jean-François Jarjavay
Jean-François Jarjavay (25 April 1815 – 22 April 1868) was a French anatomist and surgeon who was a native of Savignac-les-Églises in the department of Dordogne. He practised medicine at the Hôpital Lourcine and Hôpital Beaujon in Paris ...
is credited as the first to describe morbid processes of the SSB in 1867. Since then, histologic studies have documented that
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. It makes direct contact with the fibrous ...
may undergo
inflammatory and/or degenerative changes and many now believe that they correspond to different stages in the spectrum of disease, with long-lasting inflammation leading to
degeneration and
fibrosis
Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodelling and the formation of perma ...
.
[Arend CF. Ultrasound of the Shoulder. Master Medical Books, 2013. Read a sample chapter on the pathogenesis of shoulder bursitis a]
ShoulderUS.com
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See also
* Subacromial bursitis
Subacromial bursitis is a condition caused by inflammation of the Synovial bursa, bursa that separates the superior surface of the supraspinatus muscle, supraspinatus tendon (one of the four tendons of the rotator cuff) from the overlying coraco-ac ...
* Subcoracoid bursa
The subcoracoid bursa or subcoracoid bursa of Collas is a synovial bursa located in the shoulder.
It is located anterior to the subscapularis muscle and inferior to the coracoid process. Its function is to reduce friction between the coracobrachi ...
* Supra-acromial bursa
The supra-acromial bursa is located on the superior aspect of the acromion and normally does not communicate with the glenohumeral joint.Resnick D. Diagnosis of bone and joint disorders. 3rd edition. Philadelphia: WB Saunders Company; 1995. Supra-a ...
References
Sources
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{{Authority control
Synovial bursae
Upper limb anatomy