SHOULDER SCAPULAR REGION 93 



if the clavicle is broken medial to the attachment of the 

 ligament. 



Articulatio Acromio-Clavicularis. The acromio-clavicular 

 joint is a diarthrodial joint ; and the ligaments which bind 

 the bones together at the joint are : 



Articular Capsule : 



Superior acromio-clavicular ligament. 



Inferior acromio-clavicular ligament. 

 Accessory Ligament, not connected with the capsule : 



Coraco-clavicular. 



The superior and inferior acromio-clavicular ligaments are 

 simply thickened parts of the fibrous stratum of the articular 

 capsule. 



The superior acromio-clavicular ligament is a broad band, 

 composed of stout fibres, which is placed on the upper 

 aspect of the joint. The inferior acromio-clavicular ligament, 

 which closes the joint below, is not so strongly developed. 

 In front and behind, the two ligaments are connected with 

 each other so as to constitute a capsule. The joint should 

 now be opened to display the synovial stratum of the capsule 

 and an imperfect articular disc which is usually present. The 

 disc is wedge-shaped, and connected by its base to the 

 superior ligament, whilst its free margin is directed downwards 

 between the bones. 



The two surfaces of the joint are flat and are ovoid in 

 outline, and each slopes obliquely downwards and medially. 

 There is therefore a tendency for the clavicle to glide, upwards 

 and laterally, on to the upper surface of the acromion. The 

 tendency is counteracted by the strength of the superior 

 acromio-clavicular ligament. 



THE FRONT OF THE ARM. 



In the anterior region of the arm the following structures 

 have to be studied : 



Cutaneous veins. 



Cutaneous nerves of the arm. 



Parts of the cutaneous nerves of the forearm. 



The brachial fascia. 



