text: The above answer is correct with respect to human anatomy. However, the shoulder girdle of most vertebrates has more bones. \nIn most vertebrates, there is one important bone dorsal to the glenoid cavity (the place where the humerus articulates), that's the scapula. \nThere's another important bone ventral to the glenoid cavity, the coracoid. \nFor instance, in an amphibian there are well developed scapulae (with a suprascapular cartilage) and coracoids; and claviculae (ventral, situated anterior to the coracoids). The claviculae and the coracoid connect the shoulder girdle with the sternum.\nReptiles have many variations including other bones (interclavicula, etc.)\nBirds have strong scapulae and coracoids, and the claviculae fused in a furcula.\nPrototherian mammals (platypus and echidnas) have a reptilian-like shoulder girdle; marsupials and eutherians only have scapula, because the coracoid has fused to it forming the "coracoid apophysis". The clavicle may be present or absent; it's usually well developed in animals that use their forelimbs for different movements (for instance climbing, manipulating food) and reduced or absent in others that are specialized for running.