Which part of the scapula provides articulation for the humerus?

The glenoid fossa of the scapula is the correct answer because it is the shallow, cup-shaped socket that articulates with the head of the humerus, forming the glenohumeral joint, commonly known as the shoulder joint. This joint allows for a wide range of motion in the arm, including flexion, extension, abduction, adduction, and rotation. The structure of the glenoid fossa is specifically designed to accommodate the rounded head of the humerus, enabling a stable yet flexible connection between the upper arm and the shoulder girdle.

In contrast, the subscapular fossa is a smooth surface on the anterior aspect of the scapula that serves as an attachment site for the subscapularis muscle but does not articulate with the humerus. The coracoid process, which projects from the scapula, serves as an attachment point for muscles and ligaments, but it also does not provide a direct articulation with the humerus. Finally, the spinous process is a bony projection from the scapula that provides attachment for muscles and does not play a role in articulation with the humerus.