The CA Heads are designed to articulate with which two surfaces?

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

Answer: (A)

The key idea here is understanding which bony surfaces the CA heads are meant to interact with. The CA heads are designed to articulate with two surfaces on the shoulder girdle: the glenoid, which is the socket part of the scapula, and the acromion, which forms the roof over the joint. This pairing helps guide motion and distribute forces across two stable surfaces, rather than concentrating contact on a single area. In contrast, the humeral head is the other side of the glenohumeral joint, not a surface the CA heads are meant to articulate with in this design; the clavicle–acromion pairing describes the acromioclavicular joint, which is a different articulation altogether, and the coracoid is not a typical articulation partner for these heads.