RESEARCH.
TRIANGULARIS.
The Triangularis, when contracted creates a mouth that is an inverted smile.
The triangularis only acts upon the closed mouth. The triangularis
(also called the mouth angle depressor) has its fixed end embedded in the
bone of the chin, to the side of the centre. From there, it rises
diagonally to the corner of the mouth, where it attaches in virtually the
same place as the Zygomatic Major.
When it contracts, it draws the mouth corner and the line between the lips
sharply downwards, often extending it past the lips.
The triangularis is one of two muscles that make the mouth frown - the
other is the Mentalis. The triangularis
in action doubles the line between the lips, but the lips themselves are
only slightly changed, stretching a bit at the end. Below the mouth
corner a row of signature wrinkles appear. The lowest portion of
the nasal fold deepens. The skin outside the fold is bulged out and
pulled down.
Fig . 15 The Triangularis - Muscle Fibers.
Fig . 16 The Triangularis in action.