They are located in front of the cervical part of the vertebral column. All of them are supplied by ventral rami of cervical nerves and covered by prevertebral fascia. The posterior boundary of the retropharyngeal space is created by them. They bend the neck and the head on the neck, as a group.
The anterior vertebral group of muscles consists of:
- Rectus capitis anterior.
- Rectus capitis lateralis.
- Longus cervicis (longus colli).
- Longus capitis.
Rectus Capitis Anterior
It goes upwards and somewhat medially to be added on the inferior surface of the basiocciput just in front of the occipital condyle and originates from the anterior surface of the lateral mass of the atlas.
Rectus Capitis Lateralis
It appears from the upper surface of the transverse process of the atlas, runs upwards and laterally to be added on the inferior outermost layer of the jugular process of the occipital bone. It’s divided from rectus capitis anterior by the ventral ramus of the 1st cervical nerve, which supplies both these muscles.
Longus Cervicis (Longus colli)
This is the longest and medial of the prevertebral muscles. It stretches from anterior tubercle of the atlas to the anterior aspect of the 3rd thoracic vertebra.
The longus colli is composed of 3 parts, viz.
- Upper oblique part.
- Lower oblique part.
- Middle vertical part.
The upper oblique part originates from anterior tubercles of transverse processes of C3, C4 and C5 vertebrae, enters upwards and medially to be added on the anterior arch of the atlas to the side of the anterior tubercle.
The middle vertical part originates from the front of bodies of the upper 3 thoracic and lower 3 cervical vertebrae and ascends upward, to be added on the very front of the bodies of the 2nd, 3rd and 4th cervical vertebrae.
The inferior oblique part is the smallest. It originates from front of the bodies of the upper 2 or 3 thoracic vertebrae, runs upwards and laterally to be added onto the anterior tubercles of the transverse processes of the 5th and 6th cervical vertebrae.
Nerve Supply: The longus colli is supplied segmentally by branches from anterior primary rami of C2 to C6 spinal nerves.
Activities: It bends the neck forwards. Moreover, upper oblique part may bend the neck laterally and lower oblique part rotates the neck to the opposite side.
It appears from anterior tubercles of the transverse processes of C3, C4, C5 and C6 vertebrae, corresponding to the origin of scalenus anterior muscle and added on the inferior surface of the basilar part of the occipital bone along the side of pharyngeal tubercle. It’s narrow below and thick above and overlaps the longus colli (cervicis) muscle.
Nerve Supply: It’s supplied by branches of anterior primary rami of C1, C2 and C3 spinal nerves.
Activities: Longus capitis bends the head.