Want this question answered?
a muscle
The erector spinae
erector spinae
Erector Spinae
Erector Spinae
Erector Spinae
Iliocostalis Thoracis
True.
Erector Spinae are extensor muscles encompasing the neck and trunk. Extensor movement is antagonistic to flexor movement. Therefore, find a muscle of the neck and a muscle of the trunk that act as flexors. That should answer your question without giving away all of the milk and honey!
erector spinae, hamstrings, gastrocnemius, trapezius, quadratus lumborum
The erector spinae is the muscle you are looking for, however is should be noted that technically this is a large group of muscles.
erector spinae for spinal extension and quadratus lumborum for spinal abduction