The occipital part (in pigs and ruminants) is the dorsal part of the cleidocephalic muscle, from clavicular intersection to nuchal crest in pigs and to nuchal line and nuchal ligament in ruminants. This part is sometime called "cleidooccipital muscle".
Origin: clavicular tendon/clavicular intersection/vestigial clavicle
Insertion: nuchal ligament, nuchal line, nuchal crest on occipital bone
Action: draw the limb cranially and, acting bilaterally, to fix the neck
Nerve: accessory nerve, ventral branches of cervical nerves