Question

What does the erector muscle do?

Answer 1

I don't know which one, so go with Faith's for the first kind. "Any of the bundles of smooth muscle fibers attached to the deeper part of hair follicle, passing outwards. It moves/functions alongside the sebaceous gland to the papillartylayer of the corium, who erects hairs.This is the 'Hair Erector Muscle' "

Answer 2

Its a large muscle that originates near the sacrum and extends vertically up the length of the back.  Its located on the side of vertebral column and extends alongside the lumbar, thoracic and cervical sections of the spine.