Sternothyroid Under the Skin, Gross Anatomy

Description

Positioned in the lower anterior neck, the sternothyroid muscle is seen deep to the superficial cervical fascia and platysma, spanning from the posterior surface of the manubrium and adjacent first costal cartilage superiorly to the oblique line of the thyroid cartilage. Medial to it lie the laryngeal cartilages and midline visceral compartment, while the sternocleidomastoid forms a more lateral, oblique boundary over the carotid sheath. Superiorly, the hyoid bone sits above the thyroid cartilage, and inferiorly the clavicles and upper ribs frame the thoracic inlet. Bone landmarks of the skull, mandible, cervical vertebrae, and sternum provide orientation for the infrahyoid layer. This relationship matters when teaching strap muscle planes and the approach to the larynx and thyroid. Surgeons separate or divide the infrahyoid muscles during thyroidectomy and tracheostomy exposure, and the sternothyroid can limit superior retraction of the thyroid lobe and larynx if its attachment to the thyroid cartilage is not appreciated. It is also a key antagonist in laryngeal elevation. Dysphagia complaints after anterior neck surgery often trace back to disruption, scarring, or denervation within this infrahyoid compartment. Use this artwork for head and neck anatomy labs, otolaryngology and endocrine surgery texts, and patient-facing materials that need a clear depiction of the strap muscles relative to the thyroid cartilage and manubrium. It also supports lecture slides on swallowing mechanics, phonation, and surgical planes of the anterior neck. Anatomical accuracy verified by SciePro's Medical Advisory Board.