In the anatomical position, which structure is medial to the deltoid?

• A. Deltoid
• B. Sternum
• C. Pectoralis major
• D. Clavicle

Answer: (C)

This question tests your understanding of medial versus lateral positioning in the anatomical position. The deltoid sits on the lateral aspect of the shoulder, while the pectoralis major runs across the chest toward the midline from the sternum and medial clavicle. Because it lies closer to the midline than the deltoid, the pectoralis major is the structure medial to the deltoid. The sternum is also near the midline, and the clavicle sits more toward the shoulder, but the pectoralis major best fits the description of being medial to the deltoid in this context.