M. longissimus dorsi extends into the cervical region, where it is often distinguished as the longissimus cervicis ([Fig. 69], f″). It has been [described].
M. longus atlantis ([Fig. 71], f; [Fig. 69], d).—This represents a differentiated portion of the longissimus dorsi.
Origin from the transverse process and the side of the vertebral arch of the third cervical vertebra.
Insertion into the caudolateral angle of the wing of the atlas.
Relations.—Dorsal surface with the complexus ([Fig. 69], b), the longissimus capitis ([Fig. 69], e), and the obliquus inferior ([Fig. 71], b). Ventral surface with the scalenus ([Fig. 71], g), longissimus dorsi ([Fig. 69], f″), and levator scapulæ ([Fig. 71], h).
Action.—Extends the neck and turns the head sideways.
M. rectus capitis posterior major ([Fig. 71], a).
Origin.—The whole length of the spinous process (or crest) of the axis, or its caudal part only. It is united by a raphe to the opposite muscle. The muscle passes craniad and laterad to its
Insertion into an area ventrad of the medial part of the lambdoidal crest beneath the insertion of the complexus ([Fig. 69], b) and the biventer cervicis ([Fig. 69], a).
Relations.—Dorsal surface with the biventer cervicis ([Fig. 69], a). Ventral surface with the rectus capitis posterior medius ([Fig. 71], d) and the obliquus capitis inferior.