_Insertion_ of which is by a flat tendon into the medial third of the lambdoidal crest some distance ventrad of the free edge of the crest. Near the insertion the lateral border of the muscle is connected by an aponeurotic band to the lateral border of the transverse process of the atlas. _Relations._--Outer surface at the dorsal border with the biventer cervicis (Fig. 69, _a_); at the middle with the splenius (Fig. 73, _b_); at the ventral border with the longissimus capitis (Fig. 69, _e_) and the longissimus dorsi (Fig. 69, _f″_). Inner surface with the cervical portion of the spinalis dorsi, with the semispinalis cervicis (Fig. 71, _c_), the obliquus capitis inferior (Fig. 71, _b_), the rectus capitis posterior major (Fig. 71, _a_), and the obliquus superior (Fig. 71, _e_). _Action._--Raises the head. =M. spinalis dorsi= extends into the cervical region; it has been described. =M. semispinalis cervicis= (Fig. 71, _c_).--This represents that portion of the multifidus spinæ which extends into the cervical region. It is not composed of distinct bundles, like the multifidus of the thoracic region, but all the fibres are united into a fairly well-defined muscle. _Origin_ from the articular processes of the last five cervical vertebræ. _Insertion_ into the spinous processes of the cervical vertebræ up to the second, the largest part of the muscle being inserted into the caudal end of the spine of the atlas. _Relations._--Outer surface with the spinalis dorsi (Fig. 69, _g_) and the complexus (Fig. 69, _b_). Inner surface with the vertebræ. _Action._--Extends the neck. =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.