Which muscles are the lateral and superficial neck muscles located lateral to the thyroid lobes and strap muscles?

• A. Sternocleidomastoid muscles
• B. Platysma muscles
• C. Omohyoid muscles
• D. Masseter muscles

Answer: (A)

The sternocleidomastoid is the lateral and superficial neck muscle that sits along the side of the neck, running from the sternum and clavicle up to the mastoid process. It forms the lateral boundary near the thyroid region and lies superficial to the deeper strap (infrahyoid) muscles, making it the muscle you would identify laterally when imaging the thyroid area. The platysma is a very superficial, anterior neck muscle that covers much of the neck rather than forming a distinct lateral border. The omohyoid is one of the strap muscles and lies closer to the midline, deeper than the sternocleidomastoid. The masseter is a facial muscle near the jaw and is not part of the neck region being referenced.