The two muscles are in contact with each other proximally (close their origin), but diverge distally (towards their insertions).^[1]

Origin edit

The sternothyroid arises from the posterior surface of the manubrium of the sternum (inferior to the origin of the sternohyoid muscle), and the posterior margin of the first costal cartilage.^[1]

Insertion edit

It inserts onto the oblique line of the lamina of thyroid cartilage.^[1]

Innervation edit

The sternothyroid muscle receives motor innervation from branches of the ansa cervicalis (ultimately derived from cervical spinal nerves C1-C3).^[1]

Relations edit

The sternothyroid muscle is shorter and wider than the sternohyoid muscle and is situated deep to and partially medial to it.^[1]

Variations edit

The muscle may be absent or doubled. It may issue accessory slips to the thyrohyoid muscle, inferior pharyngeal constrictor muscle, or the carotid sheath.

Actions/movements edit

The sternothyroid muscle depresses the hyoid bone. When the hyoid bone is fixed, it instead elevates the larynx (producing an increased voice pitch).^[1]

The upward extension of a thyroid swelling (goitre) is prevented by the attachment of the sternothyroid to the thyroid cartilage. A goitre can therefore only grow to the front, back or middle but no higher.

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  Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries.
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  The fascia and middle thyroid veins.
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  Hypoglossal nerve, cervical plexus, and their branches.
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  Side view of the larynx, showing muscular attachments.
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  Sternothyroid muscle

  This article incorporates text in the public domain from page 393 of the 20th edition of Gray's Anatomy (1918)

• Photo of model at Waynesburg College musclehead/sternothyroid
• Anatomy photo:25:03-0105 at the SUNY Downstate Medical Center - "The Muscular triangle"
• PTCentral