Sternothyroid Muscle Anatomy

The sternothyroid muscle presents as a paired, flat, ribbon-like structure situated in the anterior neck region, deep to the sternohyoid muscle. This strap muscle demonstrates a shorter and broader morphology compared to its superficial counterpart, the sternohyoid.

From an embryological perspective, the sternothyroid muscle develops from the hypaxial portions of cervical myotomes.

Sternothyroid Muscle Anatomy

The Sternothyroid muscle originates from the posterior surface of the manubrium sterni and occasionally from the first costal cartilage. Its superior course terminates at the oblique line of the thyroid cartilage’s lamina, forming its insertion point. This anatomical arrangement facilitates the muscle’s primary function of drawing the larynx inferiorly.

In the anterior neck, the sternothyroid muscle maintains significant relationships with several vital structures. Anteriorly, it lies deep to the sternohyoid muscle and the investing layer of deep cervical fascia. Posteriorly, it covers portions of the thyroid gland, trachea, and inferior thyroid vessels. These relationships hold particular importance during thyroid surgery and other anterior neck procedures.

The sternothyroid muscle receives its primary innervation from the superior and inferior branches of the ansa cervicalis, specifically from spinal segments C1-C3. Understanding this innervation pattern becomes crucial during neck dissections and surgical approaches to the anterior cervical region. The muscle’s blood supply derives predominantly from the superior and inferior thyroid arteries, with additional contributions from small branches of the lingual artery.

See Also: Sternohyoid Muscle Anatomy

The sternothyroid muscle’s primary function involves depression of the thyroid cartilage, contributing significantly to laryngeal movement during swallowing and voice production. During phonation, it works in concert with other infrahyoid muscles to provide stability to the laryngeal framework.

Clinical Considerations

Understanding the sternothyroid muscle’s anatomy becomes particularly relevant in several clinical scenarios. During thyroidectomy procedures, careful identification and preservation of this muscle help maintain proper laryngeal function. The muscle often requires retraction or partial division to access the thyroid gland, necessitating careful surgical technique to prevent post-operative complications.

References & More

1. Clinically Oriented Anatomy, 8th Edition https://shop.lww.com/Clinically-Oriented-Anatomy/p/9781975140403
2. Standring, S. (2016) Gray’s Anatomy: The Anatomical Basis of Clinical Practice. Gray’s Anatomy Series 41st edn.: Elsevier Limited.