Tutorial 148 - The Rib Cage Simplified (Patreon)

Here's a rough representation of the rib cage as a solid shape with visible plane changes. It's worth memorizing this fairly complex form by drawing it from as many angles as you can. 

Start by drawing an egg shape, broad at the base, narrow at the top. For the top, we remove a chunk, at a 45 degree angle, sloping forwards. This is roughly the base of the neck. 

Now we need to remove a scooped shape from the bottom, making a kind of saddle shape. This gives us the general shape of the thoracic arch, the lower front. 

The sternum, shaped like a tie, is a flat forward facing plane. 

On the back, we cut away a section shaped like a gutter. This is where the ribs turn in to meet the backbone.

This gives us the basic shape of the rib cage.