Overview
The
suprahyoid muscles are a collection of four paired muscles, situated inferior
to the hyoid bone. Collectively, they act to depress the larynx (either
directly or indirectly via acting on the hyoid) and aid in phonation. They can
also ‘fix’ the hyoid bone, allowing digastric & geniohyoid to depress the
mandible.
Gross Anatomy
Sternohyoid |
|
Origin |
Postero-superior
aspect of manubrium and adjacent sternoclavicular joint & clavicle |
Insertion |
Lower border
of the hyoid body |
Nerve |
Ansa
Cervicalis (C1,2,3) |
Action |
Depresses
hyoid and, therefore, larynx |
Omohyoid |
|
Origin |
Inferior
belly arises from upper border of scapula & associated transverse
scapular ligament |
Insertion |
Superior
belly inserts lateral to sternothyroid on lower border of the hyoid body |
Nerve |
Ansa
Cervicalis (C1,2,3) |
Action |
Depresses
hyoid and, therefore, larynx |
Notes |
Two
bellies meet to form an intermediate tendon where they overlie the internal
jugular vein. This passes through a fibrous ‘sling’ in the investing layer of
the deep cervical fascia |
Sternothyroid |
|
Origin |
Posterior
aspect of manubrium, deep to sternohyoid |
Insertion |
Oblique
line of the thyroid cartilage |
Nerve |
Ansa
Cervicalis (C1,2,3) |
Action |
Directly depresses
larynx |
Thyrohyoid |
|
Origin |
Lower
border of the hyoid body, deep to sternohyoid and omohyoid |
Insertion |
Oblique
line of the thyroid cartilage, alongside sternothyroid |
Nerve |
C1 fibres
travelling with Hypoglossal nerve (CN XII) |
Action |
Can
either elevate larynx or depress hyoid |