The Infrahyoid Muscles
The infrahyoid muscles are a group of four muscles that are located inferiorly to
the hyoid bone in the neck. They can be divided into two groups:
o Superficial plane – omohyoid and sternohyoid muscles.
o Deep plane – sternothyroid and thyrohyoid muscles.
The arterial supply to the infrahyoid muscles is via the superior and inferior
thyroid arteries, with venous drainage via the corresponding veins.
In this article, we shall look at the anatomy of the infrahyoid muscles – their
attachments, actions and innervations.
Omohyoid
The omohyoid is comprised of two muscle bellies, which are connected by a
muscular tendon.
Attachments:
The inferior belly of the omohyoid arises from the scapula. It runs
superomedially underneath the sternocleidomastoid muscle.
It is attached to the superior belly by an intermediate tendon, which is
anchored to the clavicle by the deep cervical fascia.
From here, the superior belly ascends to attach to the hyoid bone.
Actions: Depresses the hyoid bone.
Innervation: Anterior rami of C1-C3, carried by a branch of the ansa cervicalis.
The infrahyoid muscles are a group of four muscles that are located inferiorly to
the hyoid bone in the neck. They can be divided into two groups:
o Superficial plane – omohyoid and sternohyoid muscles.
o Deep plane – sternothyroid and thyrohyoid muscles.
The arterial supply to the infrahyoid muscles is via the superior and inferior
thyroid arteries, with venous drainage via the corresponding veins.
In this article, we shall look at the anatomy of the infrahyoid muscles – their
attachments, actions and innervations.
Omohyoid
The omohyoid is comprised of two muscle bellies, which are connected by a
muscular tendon.
Attachments:
The inferior belly of the omohyoid arises from the scapula. It runs
superomedially underneath the sternocleidomastoid muscle.
It is attached to the superior belly by an intermediate tendon, which is
anchored to the clavicle by the deep cervical fascia.
From here, the superior belly ascends to attach to the hyoid bone.
Actions: Depresses the hyoid bone.
Innervation: Anterior rami of C1-C3, carried by a branch of the ansa cervicalis.
