scapula

:  either of a pair of large essentially flat and triangular bones lying one in each dorsolateral part of the thorax, being the principal bone of the corresponding half of the shoulder girdle, divided on the posterior surface into the supraspinous and infraspinous fossae by an oblique transverse bony process or spine terminating in the acromion, having a hook-shaped bony coracoid process on the anterior surface of the superior border of the bone, providing articulation for the humerus, and articulating with the corresponding clavicle—called also shoulder blade