To recognize the makings of a smile in its numerous manifestations we must first recognize the underlying anatomy.
Below we list the three critical muscles that add to a smile:
* The Zygomaticus Major - is the main "muscle of happiness". This extended muscle begins at the front area of the Zygomatic Arch (cheek bone) and attaches to the node.
When the zygomaticus major shrinks it bulges and lifts the cheek while further extending the Nasolabial Furrow or smile-line.
* The Malaris - rests on top of the zygomaticus major and is a extended, ribbon-like deep-seated muscle. It begins at the temple and attaches to and forms the bottom half of the smile-line.
The malaris is the cheek muscle. It heaves up the cheek in an outwards and back bearing making it swell and giving it the puffed cheek look.
* The Buccinator - quadrilateral muscle forms the "cheek pad". It begins on the rear, inside of the jaw and attaches to the "nodes" of the mouth.
When smiling the buccinator shrinks thus pulling at the nodes and extend the mouth.
As the mouth is extended and drawn by both the zygomaticus major and buccinator the lips are extended and flattened. So is the chin. The philtrum is reduced and the nostrils flare to some extent.
Below are still other minor muscles that add to the smile:
1. The Risorius - is a curious muscle because not everyone has one. Some people only have a risorius on one side of the face. Others have a large, extensive triangular shaped one.
The Risorius begins in the tissue of the Masseter (whose action is made use of largely for chewing) and attaches to the node of the mouth.
The risorius delicately heaves the node backwards and up. Its effect is generally seen in gentle smiles.
2. Incisivus Labii Superioris and Inferioris Superioris - The superioris does the lifting. These thing, band-like muscles begin just above the incisor tooth region and also attach to the node.
When fully shrunk, a puckering up of the lips (a kiss) is produced.
3. The Levator Labii Superioris is a narrow, quadrilateral muscle whose effect on the smile is to some extent restricted.
However, the higher part of this muscle adds to the volume of the cheek and the smile-line.
Over the three critical muscles goes the most intricate of all the facial muscles, the Orbicularis Oris which operates throughout a large range of actions and expressions.
During a smile the bottom eyelids are also pushed upward. This is the result of a secondary action where the Orbicularis Oculi (the muscle of the eye socket) shrinks.
The smile-line is deepened as it is simultaneously drawn and pushed upward and outwards. It is best to play down the sharp fold of the smile-line otherwise the smile will deteriorate into a grimace.
As the node of the mouth is drawn out and upward the skin is gathered into delicate vertical ridges.
The interstice of the mouth curves upward, stretching and flattening the lips while shortening the philtrum. The nostrils of the nose also extend as they are drawn outwards.
The upper portion of the smile-line is produced by a slender, three-part muscle called the Levator Labii Superioris Alaeque Nasi. This is the muscle that produces wrinkles in the nose during sniffing.
The elements of this muscle are the furrow section which attaches to the upper part of the smile-line; the alar section which inserts under and behind the wing of the nose (Alae Nasi); and the lip section which inserts continuously into the ridge just above the upper lip and to the philtrum.
When rendering the smile-line be careful not to over-do it. A subtle suggestion is all that is needed. Otherwise your lovely smile will quickly degenerate into a sneer.
With this we have detailed and discussed the most significant muscles that are involved in the smile. This should put you on the proper path for understand
ing the anatomy of the smile.
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