Institutio Oratoria

The neck must be straight, not stiff or bent backward. As regards the throat, contraction and stretching are equally unbecoming, though in different ways. If it be stretched, it causes strain as well, and weakens and fatigues the voice, while if the chin be pressed down into the chest it makes the voice less distinct and coarsens it, owing to the pressure on the windpipe.

It is, as a rule, unbecoming to raise or contract the shoulders. For it shortens the neck and produces a mean and servile gesture, which is even suggestive of dishonesty when men assume an attitude of flattery, admiration or fear.