The cervical part (in carnivores) is the dorsal part of the cleidocephalic muscle, from clavicular intersection to raphe of cranial portion of the neck. This part is sometime called "cleidocervical muscle".
Origin: clavicular tendon/clavicular intersection/vestigial clavicle
Action: draw the limb cranially and, acting bilaterally, to fix the neck
Nerve: accessory nerve, ventral branches of cervical nerves