5. =Trachelo-mastoideus= (M. longissimus capitis et atlantis).—This
muscle consists of two parallel, fusiform portions. It lies between the
deep face of the splenius and the ventral part of the complexus.
_Origin._—(1) The transverse processes of the first two thoracic
vertebræ; (2) the articular processes of the cervical vertebræ.
_Insertion._—(1) The mastoid process; (2) the wing of the atlas.
[Illustration: