Which is the insertion of the Zygomaticus muscle?

Which is the insertion of the Zygomaticus muscle?

• A. Origin: zygomatic bone
• B. Insertion: skin on lateral sides of the mouth
• C. Action: retracts and elevates upper lip
• D. Insertion: lips

Answer: (B)

Understanding where a muscle inserts helps explain what it can pull on when it contracts. The zygomaticus major inserts into the skin at the corner of the mouth, so when it contracts it lifts that corner upward and outward, creating a smile. That insertion location—into the skin at the lateral mouth corner—directly enables pulling the mouth corner upward. The origin is on the zygomatic bone, which is a origin detail, not the insertion. Inserting into the lips is too general for this muscle, and describing the action as retracting and elevating the upper lip doesn’t specify the correct insertion point. So placing the insertion at the skin on the lateral side of the mouth best matches how this muscle functions.

Understanding where a muscle inserts helps explain what it can pull on when it contracts. The zygomaticus major inserts into the skin at the corner of the mouth, so when it contracts it lifts that corner upward and outward, creating a smile. That insertion location—into the skin at the lateral mouth corner—directly enables pulling the mouth corner upward. The origin is on the zygomatic bone, which is a origin detail, not the insertion. Inserting into the lips is too general for this muscle, and describing the action as retracting and elevating the upper lip doesn’t specify the correct insertion point. So placing the insertion at the skin on the lateral side of the mouth best matches how this muscle functions.