SUPRAHYOID MUSCLES AND
PREVERTEBRAL MUSCLES
SUPRAHYOID MUSCLES
The suprahyoid muscles are a group of four muscles located superior to the hyoid bone of the
neck. They all act to elevate the hyoid bone – an action involved in swallowing.
The arterial supply to these muscles is via branches of the facial artery, occipital artery, and
lingual artery.
• In this article, we shall look at the anatomy of the suprahyoid muscles – their attachments,
actions, and innervation.
STYLOHYOID
Stylohyoid
The stylohyoid muscle is a thin muscular strip, which is located superiorly to the posterior belly of the
digastric muscle.
Attachments: Arises from the styloid process of the temporal bone and attaches to the lateral aspect of the
hyoid bone.
Actions: Initiates a swallowing action by pulling the hyoid bone in a posterior and superior direction.
• Innervation: Stylohyoid branch of the facial nerve (CN VII). This arises proximally to the parotid gland.
DIGASTRIC
Digastric
The digastric is comprised of two muscular bellies, which are connected by a tendon. In some cadaveric
specimens, this tendon can be seen to pierce the stylohyoid muscle.
Attachments:
The anterior belly arises from the digastric fossa of the mandible.
The posterior belly arises from the mastoid process of the temporal bone.
• The two bellies are connected by an intermediate tendon, which is attached to the hyoid bone via a fibrous sling.
Actions: Depresses the mandible and elevates the hyoid bone.
Innervation:
The anterior belly is innervated by the inferior alveolar nerve, a branch of the
mandibular nerve (which is derived from the trigeminal nerve, CN V).
• The posterior belly is innervated by the digastric branch of the facial nerve.
MYLOHYOID MUSCLE
Mylohyoid
The mylohyoid is a broad, triangular shaped muscle. It forms the floor of the oral cavity and supports
the floor of the mouth.
Attachments: Originates from the mylohyoid line of the mandible, and attaches onto the hyoid bone.
Actions: Elevates the hyoid bone and the floor of the mouth.
• Innervation: Inferior alveolar nerve, a branch of the mandibular nerve (which is derived from the
trigeminal nerve).
GENIOHYOID MUSCLE
Geniohyoid
The geniohyoid is located close to the midline of the neck, deep to the mylohyoid muscle.
Attachments: Arises from the inferior mental spine of the mandible. It then travels inferiorly and
posteriorly to attach to the hyoid bone.
Actions: Depresses the mandible and elevates the hyoid bone.
Innervation: C1 nerve roots that run within the hypoglossal nerve.
By TeachMeSeries Ltd (2021)
•
PREVERTEBRAL MUSCLES
The prevertebral muscles are a group of deep cervical muscles inside the neck
located laterally at the upper vertebral column. They are enveloped by the
prevertebral layer of the cervical fascia.
Their main task is the bending forward of the skull (ventral flexion).
Furthermore they cause a lateral flexion of the cervical column and the atlanto-
occipital joint through unilateral contraction.
LONGUS CAPITIS MUSCLE
The Longus capitis muscle originates at
the anterior tubercles of the transverse
processes of the 3rd to 6th cervical vertebrae
and inserts at the basilar part of the
occipital bone. It is innervated by branches of
the cervical plexus.
LONGUS COLLI MUSCLE
The longus colli muscle has several origins from the 3rd
thoracic to 3rd cervical vertebrae. Its insertions are
located at the upper cervical vertebrae, the transverse
processes of the 5th and 6th cervical vertebrae and the
anterior tubercle of the atlas. Hereby, one differentiates
between three portions (superior oblique, inferior oblique
and vertical portion). The innervation comes from the
cervical plexus as well.
RECTUS CAPITIS ANTERIOR AND LATERALIS
MUSCLES
• The rectus capitis anterior and the lateralis muscles make up the ventral group
of the short neck muscles. The rectus capitis anterior muscle has its origin at
the massa lateralis of the atlas, the rectus capitis lateralis muscle at the
transverse process of the atlas. Both muscles insert at the basilar part of the
occipital bone. In comparison to the dorsal group of the short neck muscles
(suboccipital muscles) which are counted among the intrinsic back muscles
they are innervated by the ventral branch of the first spinal nerve (C1).
Therefore they are considered as secondary back muscles.
