The part of a person's back where the spine curves in at the level of the waist. Most fitting reason behind the term "small of the back" is the fact that the portion where the spine curves inward toward the abdomen is relatively smaller than the rest of the back.
Referred to as the "lumbar spine", it starts about five or six inches below the shoulder blades, and connects with the thoracic spine at the top and extends downward to the sacral spine.
"Lumbar" is derived from the Latin word "lumbus," meaning lion, and the lumbar spine earns its name. It is built for both power and flexibility - lifting, twisting, and bending. See more at Spine-Health.com.
Did you think that that well-known children’s song: ‘Heads, shoulders, knees, and toes’ had taught you all the body terminology that you would ever need to know? It turns out that you were very wrong.
Check out a list of the most obscure words for body parts (via OxfordDictionaries.com) that you probably didn’t know.