Sternothyroid muscle
| Sternothyroid muscle | |
|---|---|
 Sternothyroid visible center left | |
 Section of the neck at about the level of the sixth cervical vertebra. Showing the arrangement of the fascia coli. (Sternothyroideus labeled at right, third from top.) | |
| Details | |
| Origin | Manubrium |
| Insertion | Thyroid cartilage |
| Artery | Superior thyroid artery |
| Nerve | Ansa cervicalis |
| Actions | Depresses thyroid cartilage |
| Identifiers | |
| Latin | musculus sternothyroideus |
| TA98 | A04.2.04.006 |
| TA2 | 2173 |
| FMA | 13343 |
| Anatomical terms of muscle | |
The sternothyroid muscle (or sternothyroideus) is an infrahyoid muscle of the neck.[1] It acts to depress the hyoid bone.
Structure
[edit]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 indirectly depresses the hyoid bone by means of pulling the thyroid. When the hyoid bone is fixed, it instead elevates the larynx (producing an increased voice pitch).[1]
Clinical significance
[edit]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.
Additional images
[edit]-
Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries.
-
The fascia and middle thyroid veins.
-
Hypoglossal nerve, cervical plexus, and their branches.
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Side view of the larynx, showing muscular attachments.
-
Sternothyroid muscle
References
[edit]
- ^ a b c d e f g Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. p. 582. ISBN 978-0-7020-7707-4. OCLC 1201341621.
{{cite book}}: CS1 maint: location missing publisher (link)
External links
[edit]- Photo of model at Waynesburg College musclehead/sternothyroid
- Anatomy photo:25:03-0105 at the SUNY Downstate Medical Center - "The Muscular triangle"
- PTCentral
