The CA Heads are designed to articulate with the glenoid and acromion.

• A. Glenoid and Acromion
• B. Glenoid and Clavicle
• C. Acromion and Clavicle
• D. Glenoid and Humeral head

Answer: (A)

The main idea here is how the CA head component is intended to interact with the shoulder’s bony surfaces. These heads are designed to engage both the glenoid socket and the acromion, creating a dual-contact arrangement that helps guide and constrain the humeral motion. The glenoid provides the primary articulation, allowing rotation within the socket, while the acromion acts as the superior boundary that the head can interact with during arm elevation, helping to stabilize the joint and reduce impingement. The others listed aren’t the intended articulation partners for this design surface—the clavicle relates to the AC joint rather than the glenohumeral articulation, and the humeral head is the opposing partner in the actual glenohumeral joint, not a surface the CA head would articulate with in this context.