Torso construction (rib cage, spine, pelvis, shoulder girdle)

Constructing the rib cage, spine, pelvis, and shoulder girdle as connected 3D forms that establish the torso pose.

What it is

You reduce the torso to repeatable forms: a rib cage, pelvis, spine, and shoulder girdle. You draw them as boxes, barrels, wedges, and arcs, with front, side, and back surfaces placed in simple perspective.

You block in the rib cage and pelvis, then set their tilt and twist, the spine’s curve and length, and the position of the collarbones and shoulder blades on the rib cage. The limbs and neck connect to this structure.

You use the same construction from reference or imagination. You identify the rib cage volume, place the pelvis below it, and compare their relationship. You check whether the torso leans, arches, or slumps, and whether the shoulders lift or relax.

Why it matters

Torso construction helps the chest, hips, shoulders, and spine relate as one structure. Weak control can make figures look flat, disconnected, or unstable, and can make later anatomy, clothing, and limb placement harder to organize.

You can check it when

• ✓You can block in a torso from different angles with a rib cage, pelvis, spine, and shoulder line before adding limbs.
• ✓You can show bend and twist by tilting and rotating the rib cage and pelvis separately, connecting them with a curved spine.

Related skills

• Basic mannequin
• Limbs and extremities as simple forms (arms, legs, hands, feet)
• Head and neck construction
• Figure in space (perspective, foreshortening, mental rotation)
• Torso dynamics (directions of torso and pelvis; rib cage–pelvis relationship)
• Weight, balance, and contrapposto
• Axial skeleton (spine, rib cage, pelvis)
• Shoulder girdle (scapula, clavicle)