Datasheet

14 chapter 1 ■ Blocking In the Mesh
When talking about muscles we will often refer to origins and insertions, as shown in
Figure 1.22.
The origin of a muscle is the point at which it originates on the skeleton. Muscles pull
toward their origin. An easy way to determine the origin of any muscle is to find the point at
which the muscle moves the least. For example, see Figure 1.23. The Pectoralis muscle origi-
nates on the sternum and inserts on the humerus or upper arm bone. The head that attaches
to the arm has the most range of motion, so it is the insertion. The shape of a muscle may
change as it moves, but the origin and insertion never change; they are attached to the
skeleton. So by knowing these points you understand how to place the muscle in any pose.
You also know what direction the muscle pulls in and what its function is. If you know the
start and end points of a muscle, deciphering its function is rather simple. Just remember
that muscles pull toward the origin, and you will quickly realize the purpose of the muscle
in question. Combine this with useful clues contained in the muscle name, and you have a
wealth of information about the form in question.
As we discuss each part of the body in this book,
we will be looking at the major muscle forms including
their origins and insertions. It’s important to under-
stand what these terms mean and how they apply, so
as we come across them later you will understand their
importance. A simple way to remember the difference
between origins and insertions is that a muscle pulls in
the direction of its origin.
One last point I want to mention here about
muscles. As we start sculpting, I will often refer to
planes and plane breaks. This is simply a way to define
a structure and apply an angular quality to the surface
of the figure. For years I considered the muscles to be
somewhat soft forms inside the body pressed against
each other. It wasn’t until I started doing cadaver dis-
section that it came to my attention that the muscles
are very structural bodies that maintain their shapes
independent of each other.
Spine of
the scapula
Supraspinatus
Infraspinatus
Figure 1.21 The supra- and infra-spinatus muscles
Insertion
Origin
Belly
Figure 1.22 The parts of a muscle
Origin
Insertion
Figure 1.23 Pectoralis origin and insertion
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