LIGAMENTS OF THE SCAPULA, 



151 



2. Scapulo- clavicular Articulation. The ligaments of tl./e scapular end 

 of the clavicle are, the 



Superior acromio-clavicular, 

 Inferior acromio-clavicular, 

 Coraco-clavicular (trapezoid and conoid), 



Interarticular fibre-cartilage, 



Two synovial membranes. 



The superior acromio-clavicular ligament is a moderately thick plane 

 of superimposed fibres passing between the extremity of the clavicle and 

 the acromion, upon the upper surface of the joint. 



The inferior acromio-clavicular ligament is a thin plane situated upon 

 the under surface. These two ligaments are continuous with each other 

 in front and behind, and form a complete capsule around the joint. 



The cor aco~ clavicular ligament (trapezoid, conoid) is a thick fasciculus 

 of ligamentous fibres, passing obliquely between the base of the coracoid 

 process and the under surface of the clavicle, and holding the end of the 

 clavicle in firm connexion with the scapula. When seen from before, it 

 has a quadrilateral form : hence it is named trapezoid ; and examined from 

 behind, it has a triangular form, the base being upwards ; hence another 

 name, conoid. 



The inter articular fibro-cartilage is often indistinct, from having partial 

 connexions with the fibro-cartilaginous surfaces of the two bones between 

 which it is placed, and not unfrequently absent. When partial, it occu- 

 pies the upper part of the articulation. The synovial membranes are very 

 delicate. There is, of course, but one, when the fibro-cartilage is incom- 

 plete. 



Actions. The acromio-clavicular articulation admits of two movements, 

 the gliding of the surfaces upon each other ; and the rotation of the sca- 

 pula upon the extremity of the clavicle. 



3. The Proper ligaments of the Scapula 

 are the Fi s- 86 -* 



Coraco-acromial, 

 Transverse. 



The coraco-acromial ligament is a broad 

 and thick triangular band, which forms a pro- 

 tecting arch over the shoulder joint. It is 

 attached by its apex to the point of the acro- 

 mion process, and by its base to the external 

 border of the coracoid process its whole 

 length. This ligament is in relation above 

 \vith the under surface of the deltoid muscle ; 

 and below with the tendon of the supra-spi- 

 natus muscle, a bursa mucosa being usually 

 interposed. 



The transverse or coracoid ligament is a 

 narrow but strong fasciculus which crosses 



* The ligaments of the scapula and shoulder joint. 1. The superior acromio-clavicu- 

 lar ligament. I. The coraco-clavicular ligament ; this aspect of the ligament i named 

 trapezoid. 3. The coraco-acromial ligament. 4. The transverse ligament. :. The 

 capsular ligament. 6. The coraco-humeral ligament. 7. The long tendon, of -he bicon< 

 issuing from the capsular ligament, and enter ng the bicipital groove. 



