Duchenne states that the pyramidal muscle of the nose is less under
the control of the will than are the other muscles round the eyes.
He remarks that the young man who could so well act on his grief-muscles,
as well as on most of his other facial muscles, could not contract the
pyramidals.[5] This power, however, no doubt differs in different persons.
The pyramidal muscle serves to draw down the skin of the forehead
between the eyebrows, together with their inner extremities.
The central fasciae of the frontal are the antagonists of the pyramidal;
and if the action of the latter is to be specially checked,
these central fasciae must be contracted. So that with persons having
powerful pyramidal muscles, if there is under the influence of a bright
light an unconscious desire to prevent the lowering of the eyebrows,
the central fasciae of the frontal muscle must be brought into play;
and their contraction, if sufficiently strong to overmaster the pyramidals,
together with the contraction of the corrugator and orbicular muscles,
will act in the manner just described on the eyebrows and forehead.
When children scream or cry out, they contract, as we know,
the orbicular, corrugator, and pyramidal muscles, primarily for
the sake of compressing their eyes, and thus protecting them
from being gorged with blood, and secondarily through habit.
Pages:
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283