4 The pectorals

When we turn our attention to the pectorals, it is useful to examine how this muscle attaches to the bones in a more complex way.

We can separate this muscle into three distinct portions:

The clavicular portion – This section lays on top and attaches to the clavicle and the lowest point on the humerus or arm bone.

The sternal portion – One layer deeper and attaches to the sternum and the middle of the humerus.

The abdominal portion – This section is the deepest and attaches to the abdomen and the highest point on the humerus.

But what is the point of learning about this spiralling nature of the muscle? After all, on all but the most impressively muscular physiques, these sections will not be clearly delineated on the human form.

The interesting thing about this point is that, while it isn’t explicitly clear on the form, it is always suggested! On the right, as you can see, there are three distinct angles present near the armpit shadows of the pectoral. Note that each of these angles, while not distinct through the entire form, do lead to exactly the correct positions on the clavicle, sternum and abdomen.

These three angles will always show up on the form, will always lead to the same places on the form, and are always something to look for when trying to refine this interesting area. See if you can spot them in your next drawing!