The inferior maxillary or lower jawbone
is the lower border of the face. It is shaped
like a horseshoe, its extremities ascending
to fit into the temporal portion of the ear.
It is a mandible, working on the principle
of a hinge moving down or up as the mouth
opens or closes, but with a certain amount
of play, sideways and forward, so that
when worked by the masseter muscles the
food is not simply hammered or flattened,
but ground by the molar or grinding teeth.
The masseter muscle extends from under
the span of the zygomatic arch to the lower
edge and ascending angle of the lower jaw.
It is the large muscle raising the lower jaw,
used in mastication. It fills out the side of
the face, marking the plane which extends
from the cheek bone to the angle of the jaw.
1 TEMPORAL
2 MASSETER
DRAWING THE HEAD
Begin by drawing with straight lines the general outline of
the head.
Then draw the general direction of the neck from its center,
just above the Adam's apple, to the pit, at the junction of the
collar bones. Now outline the neck, comparing its width and
length with the head.
Draw a straight line through the length of the face, passing
it through the root of the nose, which is between the eyes, and
through the base of the nose where the nose centers in the
upper lip.
Draw another line from the base of the ear at a right angle
to the one you have just drawn.
On the line passing through the center of the face, measure
off the position of the eyes, mouth and chin. A line drawn
through these will parallel a line drawn from ear to ear, inter-
secting, at right angles, the line drawn through the vertical
center of the face.