Anatomy def: bundle of vertically-oriented back muscles, one on each side of the spine; straighten the back and rotate the trunk from left to right.
Outlander def: paired columns of awesome, delightful Jamie muscles that flank the midline spinal groove.
Learn about erector spinae in Anatomy Lesson #10 “Jamie’s Back” or “Aye, Jamie’s Back!”
Read about Jamie’s erector spinae as Claire muses about these rounded columns of back muscles in Outlander book:
I thought with some regret that it must have been quite a beautiful back at one time. His skin was fair and fresh, and the lines of bone and muscle were still solid and graceful, the shoulders flat and square-set and the backbone a smooth, straight groove cut deep between the rounded columns of muscle that rose on either side of it.
See Jamie’s erector spinae muscles flex and bulge in rebellion at Dougal’s daring “usury” in Starz episode 105, Rent (also see his erector spine in episodes 102, 106, 107, 108, 109, 110, 112, 115 16...pretty much in every episode. Snort!)
A deeply grateful,
Outlander Anatomist