VENTRAL CERVICAL MUSCLES 269 



scalenus ventralis) is attached to the transverse processes of the sixth, fifth, and 

 fourth cervical vertebrae. 



Action. — The neck is flexed or inclined laterally, according as the niuscles act 

 together or singly. If the neck be the fixed point, the muscle may have a respira- 

 tory action by pulling forward or fixing the first rib. 



Structure. — The dorsal part is composed of several small fleshy bundles. The 

 ventral portion, which is much larger, is almost entirely fleshy, and not so divided. 



Relations. — Superficially, the anterior deep pectoral, brachiocephalicus, and 

 omo-hyoideus muscles, the phrenic nerve, and branches of the brachial plexus; 

 deeply, the vertebrae, the longus colli and intertransversales muscles, the cesoph- 

 agus (on the left side), the trachea (on the right side), the vertebral vessels, 

 the vagus, sympathetic, and recurrent nerves. The roots of the brachial plexus 

 form a flat anastomosis, which lies between the two parts of the muscle. The 

 brachial vessels cross the ventral edge close to the first rib. 



Blood-supply. — Carotid, verteljral, and inferior cervical arteries. 



Nerve-supply. — Ventral branches of the cervical nerves. 



7. Cervicalis ascendens.^ — This muscle is the cervical continuation of the 

 longissimus costarum, and is sometimes regarded as a part of the scalenus, with 

 which it is partially united. It consists of three or four bundles which are attached 

 to the transverse processes of the last three or four cervical vertebrae and the first 

 rib. 



Action. — To extend the neck or to flex it laterally. 



Relations. — Superficially, the brachiocephalicus and anterior deep pectoral; 

 deeply, the scalenus and intertransversales. 

 Blood-supply. — Vertebral artery. 

 Nerve-supply. — Cervical nerves. 



8. Rectus capitis ventralis major (M. longus capitis). — This is the largest 

 of the three special fiexors of the head, and lies along the ventro-lateral surface 

 of the anterior cervical vertebrae and the base of the cranium. 



Origin. — The transverse processes of the fifth, fourth, and third cervical ver- 

 tebrae. 



Insertion. — The tubercles at the junction of the basilar part 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 in- 

 creases 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 brachiocephalicus and omo-hyoideus, the mandib- 

 ular gland, the carotid artery (which lies along the ventral border), the occipital 

 and internal carotid arteries, and the tenth, eleventh, and sympathetic nerves; 

 deeply, the vertebrae, the longus colli, intertransversales, and the rectus capitis 

 ventralis minor. 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. 



9. Rectus capitis ventralis minor (M. rectus capitis ventralis). — This is a small 

 muscle which lies dorsal to and under cover of the preceding one. 



Origin. — The ventral arch of the atlas. 



Insertion. — The basilar part of the occipital bone, close to the preceding muscle. 



Action. — To flex the atlanto-occipital articulation. 



Structure. — Fleshy. 



1 This muscle is also known as the ilio-costalis cervicis. 



