Assertion: hedgehog's muscle | /r/CapableOf | run the length of the back
Facets:
Source sentences:
text: The hedgehogs quills are controlled by muscles running the length of the back.
text: The hedgehog's famous ability to roll into a tight ball is an effective deterrent to predators and with two muscles that run the length of the back they can orientate their spines to point towards any danger.