RESEARCH.
CORRUGATOR.
The Corrugator is the chief muscle used in the act of crying, scowling
and fear. The corrugator's basic action is to pull the eyebrows down
and bring them closer together. It is in fact two muscles that do
the work, the corrugator and the Procerus. The two muscles always
contract simultaneously, thus they are considered as one muscle.
The corrugator has muscle fibres that radiate upward from the bridge of
the nose and go into the skin of the lower, middle brow. (see
fig 08) The procerus is fan shaped. The base of the
fan is fixed into the nasal bone where the bone meets the cartilage.
The upper, moveable end is attached to the skin in the area between the
two eyebrows.
When a person frowns the inner ends of the eyebrows move together and downward;
the skin in between is bunched and wrinkled. (see
fig 09) The entire eyebrow appears tipped downwards.
There is also a subtle movement forwards. The bunching of the skin
above the eye creates a sort of shelf, projecting outward. The movement
of the eyebrows also affects the area between the eyebrows, where two or
three very deep vertical wrinkles tend to form.
The downward pressure and forward pressure of the brow drags the skin below
along with it. A new, sharply defined, skin fold appears above the
eye, partly closing it. The minimum elements necessary to recognizably
depict a frowning brow are these: inward slanting eyebrows, vertical in-between
creases, and the extra low level of the brow. The other, more subtle
changes enhance the effect.
Fig . 08 - Corrugator Muscle Fibres. Fig . 09 - The Corrugator in action.