134 THE MUSCLES. 



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 

 vertebrae. 



Insertion into the spinous processes of the cervical vertebrae 

 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, ). Inner surface with 

 the vertebrae. 



Action. Extends the neck. 



M. longissimus dorsi extends into the cervical region, 

 where it is often distinguished as the longissimus cervicis 

 (Fig. 69, /""). It has been described. 



M. longus atlantis (Fig. 71, f; Fig. 69, d}. This repre- 

 sents 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, ), 

 the longissimus capitis (Fig. 69, e), and the obliquus inferior 

 (Fig. 71, ft). Ventral surface with the scalenus (Fig. 71, g), 

 longissimus dorsi (Fig. 69, _/"), and levator scapulae (Fig. 

 71, //). 



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, d) 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. 



