The |scapula| (shoulder blade) is a rougly triangular bone which, with the |clavicle|, forms the pectoral, or shoulder, girdle. The |humerus|, or upper arm bone, articulates with the |scapula| to form the |shoulder joint|. This articulation takes place at the |glenoid cavity|, located at the upper, lateral angle of the |scapula|. The ~posterior~ of the |scapula| features a laterally running |spine| ,which separates the ~posterior~ surface into two unequal areas. This |spine| continues laterally and projects in the |coracoid process| and the |acromion| (which articulates with the medial end of the |clavicle|). Both of these projections serve as sites of attachment for connective tissue, and the |spine| and |acromion| anchor the |trapezius| and |deltoids|, specifically. These connections give the pectoral girdle a high degree of both flexibility and strength.
