Content Reviewers:Viviana Popa, MD, Scott Caterine, BSc (Hons.), MSc, MB, BCh, BAO (Hons.)
The neck is the anatomical region between the base of the cranium superiorly and the clavicles inferiorly and it joins the head to the trunk and limbs, serving as a major conduit for structures passing between them.
The neck contains superficial structures, located in the anterior and posterior triangles and deep structures, like the cervical viscera and the prevertebral muscles.
Now, the prevertebral muscles are deep to the prevertebral layer of the deep cervical fascia and they are divided into anterior prevertebral muscles and lateral prevertebral muscles.
The anterior prevertebral muscles are located directly posterior to the retropharyngeal space and medial to the neurovascular plane of the cervical plexus, brachial plexus and subclavian artery, and they are represented by longus colli, longus capitis, rectus capitis anterior and anterior scalene muscles.
Now, the longus colli originates from the bodies of C5 to T3 vertebrae and the transverse processes of C3 to C5 vertebrae.
It inserts onto the anterior tubercle of the C1 vertebra, the bodies of the C2 to C4 vertebrae and the transverse processes of C3 to C6 vertebrae.
It’s innervated by the anterior rami of C2 to C6 spinal nerves
When it contracts bilaterally, it produces flexion of the neck and when it contracts unilaterally it produces rotation to the opposite side.
It’s innervated by the anterior rami of spinal nerves C1 through C3 and its contraction results in flexion of the head at the atlanto-occipital joint.
Next, the rectus capitis anterior originates from the anterior surface of the lateral mass of the atlas, which is the first cervical vertebra, and inserts onto the base of the cranium, anterior to the occipital condyles.
It’s innervated by branches from the loop between C1 and C2 spinal nerves and its contraction also results in flexion of the head at the atlanto-occipital joint.
Finally, the anterior scalene muscle originates from the anterior tubercles of the transverse processes of the C3 to C6 vertebrae and inserts onto the first rib.
It’s innervated by the anterior rami of spinal nerves C4 to C6.
It functions to elevate the first rib during forced inspiration, and when the rib is fixed, bilateral contraction produces flexion of the neck and unilateral contraction produces lateral flexion of the neck.
Next up, there are the lateral prevertebral muscles, located posterior to the neurovascular plane of the cervical and brachial plexuses and subclavian artery.
It’s innervated by branches from the loop between C1 and C2 spinal nerves and when it contracts, it stabilizes and flexes the atlanto-occipital joint.