Part II · Anatomy · Chapter 17 of 31

Anatomy V: The torso

The torso is two boxes — ribcage and pelvis — linked by a flexible column. Almost every expressive pose comes from tilting, twisting or bending those two boxes against each other.

Two masses

Draw the ribcage as an egg or a box tipped slightly back, and the pelvis as a shorter, wider box. Between them the belly and the lower back stretch on one side and squash on the other. On the squashed side you get folds; on the stretched side a long, smooth curve.

In contrapposto the pelvis tilts down towards the relaxed leg while the shoulders tilt the other way. Michelangelo's Libyan Sibyl studies show a back in strong twist: the shoulder blades turn while the pelvis stays put.

The shoulder girdle

The shoulders are not fixed to the ribcage. The collarbones and shoulder blades float over it, held by muscles, so lifting an arm also lifts and rotates the shoulder blade. When the arm rises above the head, the deltoid and the shoulder blade move together and the armpit opens.

The back

The spine sits in a groove between two thick columns of muscle (the erector spinae). Look for the dimples over the sacrum, the triangle of the trapezius and the V of the latissimus dorsi. In a seated pose these forms soften and the back rounds.

Reference table

Form	What it does	Drawing tip
Ribcage	Protects the heart and lungs	Egg shape; the front ends in an arch below the chest
Pelvis	Supports the trunk, connects the legs	Box; mark the two hip points at the front
Spine	Lets the masses bend and twist	Draw it as a curved line first
Shoulder blade	Moves with the arm	Changes the back's silhouette as the arm moves
Abdomen	Flexes and twists the trunk	Squashes on one side, stretches on the other