The Prevertebral Muscles
The prevertebral muscles are a group of deep cervical muscles 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).
- 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: has several origins from the 3rd thoracic to 5th 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 is effected by the cervical plexus as well.
- Rectus capitis anterior and 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.
The prevertebral muscles are - despite their small size - the most important antagonists of the large cervical spine extensors such as the trapezius muscle and levator scapulae muscle. They play an enormous role in the connection and stabilization of the cervical column and the skull. Inappropriate load (e.g. sitting for long periods) and abnormal pattern of posture (e.g. monotonously pulling up the shoulders at the workplace) cause a permanent contraction of the cervical spine extensors which cannot be balanced by the prevertebral muscles in the long term. Consequences are neck pain, indurations, degenerative processes of the vertebral bodies up to a pathological inward curvature of the cervical column (hyperlordosis).