noun
torso
TOR-soh/ˈtɔːrsəʊ/
The central part of the human body, excluding the head and limbs.
The dress form shows a torso without head or limbs.

Etymology
A word for a stalk or stem developed into a name for a statue's trunk, considered apart from its head and limbs. It later extended to the same central portion of a living body.
In context
if your arm is at your side and you suddenly lift it to the top of your head you'll notice that your torso kind of shifts