On both sides, the rectus capitis anterior muscle is one of the deep muscles of the neck. Deep to the prevertebral fascia, it arises from the anterior surface of the lateral mass of the atlas (C1 vertebra). Passing superomedially, it inserts into the basilar occipital bone anterior to the ipsilateral occipital condyle.
It is innervated by the anterior primary rami of the first cervical nerve (C1).
Rectus capitis anterior acts to flex the head on the neck at the atlanto-occipital joint.