_Insertion._—The tubercles at the junction of the basilar process of the occipital bone with the body of the sphenoid. _Action._—Acting together, to flex the head; acting singly, to incline it to the same side also. _Structure._—The origin of the muscle is by fleshy digitations. The belly increases in size by the union of these digitations, reaching its maximum at the axis. It then diminishes, passes toward the median plane, and terminates on a rounded tendon. _Relations._—Superficially, the mastoido-humeralis, omo-hyoideus, and rectus capitis anticus minor, the submaxillary gland, the carotid artery (which lies along the lower border), the occipital and internal carotid arteries, and the tenth, eleventh, and sympathetic nerves; deeply, the vertebræ, the longus colli, intertransversales, and the small straight muscle. The terminal part of the muscle lies in contact with its fellow above the pharynx and between the guttural pouches. _Blood-supply._—Carotid, vertebral, and occipital arteries. _Nerve-supply._—Ventral branches of the cervical nerves. 8. =Rectus capitis anterior minor= (M. rectus capitis ventralis).—This is a small muscle which lies under cover of the preceding one. _Origin._—The ventral arch of the atlas. _Insertion._—The basilar process, close to the preceding muscle. _Action._—To flex the occipito-atlantal articulation. _Structure._—Fleshy. _Relations._—Below, to the preceding muscle; above, to the atlas, occipito-atlantal articulation, and the basilar process; externally, to the rectus capitis lateralis and the guttural pouch. _Blood-supply._—Occipital artery. _Nerve-supply._—Ventral branch of the first cervical nerve. 9. =Rectus capitis lateralis.=—This is a still smaller, entirely fleshy muscle, which lies for the most part under the small oblique muscle. _Origin._—The atlas, external to the preceding muscle. _Insertion._—The paramastoid or styloid process of the occipital bone. _Action._—The same as the preceding muscle. _Structure_.—Fleshy. _Relations._—Superficially, the small oblique muscle, the occipital vessels, and the ventral branch of the first cervical nerve. _Blood-supply._—Occipital artery. _Nerve-supply._—Ventral branch of the first cervical nerve. 10. =Longus colli.=—This muscle covers the ventral surface of the vertebræ, from the sixth thoracic to the atlas, and is united with its fellow. It consists of two portions, thoracic and cervical. _Origin._—(1) Thoracic portion, the bodies of the first six thoracic vertebræ; (2) cervical portion, the transverse processes of the cervical vertebræ. _Insertion._—(1) Thoracic portion, the bodies and transverse processes of the last two cervical vertebræ; (2) cervical portion, the bodies of the cervical vertebræ and the tubercle on the ventral surface of the atlas. _Action._—To flex the neck.