Coracoid

The coracoid or Os coracoideum ( to Greek κόραξ Corax, Raven '), German or coracoid coracoid bone, is one of the three original bones of the shoulder girdle in vertebrates.

In bony fish ( Osteichthyes ) the coracoid forms with the shoulder blade (scapula ) a U-shaped bone support. In the amphibians occurs yet another small bone, the procoracoid, added. In the recent reptiles the coracoid is usually only cartilaginous, in snakes ( Serpentes ) only as a residual available.

In birds ( Aves) is the coracoid the strongest bone of the shoulder girdle and is available as rod-shaped, vertically oriented support and slightly to the side in front of the chest (thorax ). This is directed towards the abdomen ( ventral) to the sternum ( sternum) and move upward ( dorsal) with the scapula, clavicle and humerus (humerus ), that participates in the formation of the shoulder joint.

In mammals ( Mammalia), a coracoid is formed only at the monotremes ( Monotremata ) and some manatees. In the other mammals it is one located on the shoulder blade extension, the coracoid process ( coracoid process ) regressed.