the masseter and the sternocleidomastoid

[japan rocks/andromeda]

as we all know the masseter is the mussle that pulls on the jaw and we all know that the sternocleidomastoid is in the neck and i dont really know what it does ♥

[tomgwyther]

http://en.wikipedia.org/wiki/Sternocleidomastoid_muscle

 

The SCM moves your head around. Here'a a wikipedia link about it with lots of interesting information, including...

Creature designers often include the sternocleidomastoid muscle in models of alien characters when they want them to seem attractive and familiar to human viewers due to the muscle's uniqueness as a mammalian feature.