Which scapular landmark articulates with the clavicle at the acromioclavicular joint?

• A. Coracoid process articulates with the humerus.
• B. Glenoid cavity articulates with the radius.
• C. Scapular spine forms the knee joint.
• D. Acromion articulates with the clavicle at the acromioclavicular joint.

Answer: (D)

This question focuses on where the clavicle meets the scapula. The acromion, a bony projection at the outer end of the scapular spine, forms the acromioclavicular joint with the lateral (acromial) end of the clavicle. This articulation is what you feel as the tip of the shoulder and it allows small gliding movements that help position the scapula during arm movement. The coracoid process is just a projection for muscle and ligament attachments and does not form a joint with the humerus. The glenoid cavity is the socket for the humeral head, not a connection with the radius. The scapular spine is a ridge on the posterior scapula and irrelevant to the knee joint.