Asset Creation: Maya Character Creation - Creating Games with Unity and Maya - page 190

Why?
Keep extruding until there is a Phantom of the Opera-esque mask
complete. Do not worry about the mass at the end of the nose.
The Mouth
Step 28: Repeat steps 15 to 27 to create the mouth. Again, the flow is to
create a new polygon, then extrude the edges around. The biggest difference
here is that instead of creating a complete ring, create a half ring ( Figure 8.15 ).
Figure 8.15 First pass of the mouth.
Step 29: Create an oral cavity. Do this by selecting the edges on the inside
of the mouth and extruding back into the head. Finally take the very last
collection of vertices and snap them to the center (hold X while using
the Move tool). Marquee select these vertices and choose Polygons>Edit
Mesh>Merge ( Figure 8.16 ).
Figure 8.16 Oral cavity creation.