The expressions of these prime feelings are instinctual, the muscle interactions and activities are involuntary. In general, the facial muscles are fragile, finely in step and easily seen because they lie just under the surface.



The facial muscles not only communicate moods and expressions they also display sympathetic characteristics. For instance, when we are threading a needle we usually pucker our lips to "aid" the thread through the needle's eye.

All facial expressions involve the muscles and other parts of the mouth. Therefore, to comprehend the facial expressions we must first comprehend the mouth which is more than just the lips.

The mouth region extends from the base of the nose to the Mentolabial Sulcus, i.e., the sulk-line of the chin. The mouth is a convex form and wraps around the muzzle of the face.

Drawing the mouth should always begin with the drawing of the Interstice, i.e., the horizontal line where the lower and upper lips meet. The lips wrap around the convex outcrop of the dental arch and the interstice roughly corresponds to the middle portion of the front, upper teeth.

Note that the Nodes in the corners of the mouth are lower than the middle of the interstice, except in a smile when the facial muscles pull up the nodes.

The lips, or Labia, are composed of mucous membrane whose redness is the result of blood capillaries lying just under the surface.

The upper lip consists of three shapes. In the middle is the Tubercle which is non-muscular and add to the 'V' form of the top where it comes together with the base of the Philtrum. The Philtrum is the stretched, vertical channel that extends from the base of the nose to the tubercle of the top.

The philtrum, which means "love drop", is bounded by ridges on each side. Practically every starting draftsperson overextends the philtrum, thus placing the mouth too low.

The other 2 components of the upper lip are 2, horizontal stretched shapes. The muscles here, however, are the observable ridges of the middle vertical fibers of the Orbicularis Oris whose activity results in the pursing up of the lips. The many facial muscles fastened to the nodes of the mouth do the pulling and pushing.

The upper lip is flatter than the bottom lip. It is a downward facing plane and commonly appears darker than the bottom lip. There is a small up-plane on the vermillion border of the top that quite often catches a gentle light. For most people, the upper lip tucks into the nodes.

The bottom lip commonly stops a little short of the nodes. The bottom lip is heavier and fuller. It consists of two stretched shapes that give it a more squared-off look than the upper lip.

Slightly below the vermilion border of the bottom lip is a raised edge that develops laterally and is more noticeable at the nodes.

The vermilion border of the bottom lip should not be drawn with a distinct line, it has to be suggested more than drawn. Otherwise it will look like lipstick.

The bottom lip is an up-plane and will often catch a highlight. Like the upper lip, the ridges of the middle vertical fibers of the orbicularis oris form the texture of the bottom lip.

The base of the mouth region is at the mentolabial. Shaping at the bottom edge of the lower lip's two stretched shapes are two columnar tubes that radiate diagonally downward. These are the Pillars of the Mouth. This is a down plane and thus will fall into shadow.

With this we end the complete description of the things that make the mouth and ultimately the smile.