Which muscle originates from ribs 2-6, sternum, and clavicle?

Which muscle originates from ribs 2-6, sternum, and clavicle?

• A. Deltoid
• B. Pectoralis Major
• C. Latissimus Dorsi
• D. Serratus Anterior

Answer: (B)

The muscle described by origins on ribs 2–6, the sternum, and the clavicle is the pectoralis major. It has two heads: a clavicular head that attaches to the clavicle, and a sternocostal head that attaches to the sternum and the costal cartilages of the upper ribs (commonly ribs 2–6). This combination of clavicle plus sternum and 2–6 ribs exactly matches its origin pattern, which is why this muscle is the best fit. The other muscles have different starting points: deltoid originates from the clavicle and parts of the scapula, latissimus dorsi from the lower back and iliac crest with some ribs, and serratus anterior from the upper ribs along the side of the chest.

The muscle described by origins on ribs 2–6, the sternum, and the clavicle is the pectoralis major. It has two heads: a clavicular head that attaches to the clavicle, and a sternocostal head that attaches to the sternum and the costal cartilages of the upper ribs (commonly ribs 2–6). This combination of clavicle plus sternum and 2–6 ribs exactly matches its origin pattern, which is why this muscle is the best fit. The other muscles have different starting points: deltoid originates from the clavicle and parts of the scapula, latissimus dorsi from the lower back and iliac crest with some ribs, and serratus anterior from the upper ribs along the side of the chest.