SCAPULO-CLAVICULAR LIGAMENTS. 



119 



dislocation of the 



Fig. 52.* 



The rupture of the rhomboid ligament in 

 sternal end of the clavicle, gives 

 rise to the deformity peculiar to 

 this accident. 



The inter articular fibro-cartilage is 

 nearly circular in form, and thicker 

 at the edges than in the centre. It 

 is attached above, to the clavicle ; 

 below to the cartilage of the first 

 rib ; and throughout the rest of its 

 circumference to the anterior and 

 posterior sterno-clavicular liga- 

 ment ; it divides the joint into two 

 cavities, which are lined by distinct 

 synovial membranes. This cartilage is sometimes pierced through 

 its centre, and not unfrequently absorbed to a greater or less extent, 

 particularly at its lower part. 



2. Scapula-clavicular Articulation. The ligaments of the scapular 

 end of the clavicle are, the 



Superior acromio-clavicular, 

 Inferior acromio-clavicular, 

 Coraco-clavicular (trapezoid and conoid), 



Interarticular fibro-cartilag e, 



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 coraco-clavicular ligament (trapezoid, conoid) is a thick fasci- 

 culus 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 name 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 occupies the upper part of the articulation. The 



*The ligaments of the sterno-clavicular and costo-stcrnal articulations. 1. The 

 anterior sterno-clavicular ligament. 2. The inter-clavicular ligament. 3. The costo- 

 clavicular or rhomboid ligament, seen on both sides. 4. The inter-articular fibro- 

 cartilage, brought into view by the removal of the anterior and posterior ligaments. 

 5. The anterior costo-sternal ligaments of the first and second ribs. 





