Answer
The two tru joints formed between the scapula and other bones are the acromioclavicular joint and the glenohumeral joints. The acromioclavicular joint is formed between the acromion of the scapula and the lateral ( acromial) end of the clavicle; the glenohumeral joint is formed between the glenoid cavity of the scapula ( just inferior to the acromion) and the head of the humerus.
Work Step by Step
In the acromioclavicular joint the acromion of the scapula articulates with the lateral (acromial) end of the clavicle. This is a diarthrosis.
In the glenohumeral joint the glenoid cavity of the scapula accepts the head of the humerus. This is a shallow ball and socket joint.
The so-called scapulo-thoracic joint between the convex posterior thoracic ( first few ribs) and the concave anterior surface of the scapula is not a really a joint. Several muscle are attached in this area, and the movement of the scapula over the the surface of the thoracic cage facilitates and supports several type of arm and shoulder movements
