Henle (`Handbuch d. Syst. Anat. 1858, B. i. s. 139) agrees with Duchenne that this is the effect of the contraction of the _pyramidalis nasi_.
 These consist of the _levator labii superioris alaeque nasi_, the _levator labii proprius_, the _malaris_, and the _zygomaticus minor_, or little zygomatic. This latter muscle runs parallel to and above the great zygomatic, and is attached to the outer part of the upper lip. It is represented in fig. 2 (I. p. 24), but not in figs. 1 and 3. Dr. Duchenne first showed (`Mecanisme de la Physionomie Humaine,' Album, 1862, p. 39) the importance of the contraction of this muscle in the shape assumed by the features in crying. Henle considers the above-named muscles (excepting the _malaris_) as subdivisions of the q_uadratus labii superioris_.
The raising of the upper lip draws upwards the flesh of the upper parts of the cheeks, and produces a strongly marked fold on each cheek,--the naso-labial fold,--which runs from near the wings of the nostrils to the corners of the mouth and below them. This fold or furrow may be seen in all the photographs, and is very characteristic of the expression of a crying child; though a nearly similar fold is produced in the act of laughing or Smiling.
 Although Dr. Duchenne has so carefully studied the contraction of the different muscles during the act of crying, and the furrows on the face thus produced, there seems to be something incomplete in his account; but what this is I cannot say. He has given a figure (Album, fig. 48) in which one half of the face is made, by galvanizing the proper muscles, to smile; whilst the other half is similarly made to begin crying. Almost all those (viz. nineteen out of twenty-one persons) to whom I showed the smiling half of the face instantly recognized the expression; but, with respect to the other half, only six persons out of twenty-one recognized it,--that is, if we accept such terms as "grief," "misery," "annoyance," as correct;--whereas, fifteen persons were ludicrously mistaken; some of them saying the face expressed "fun," "satisfaction," "cunning," "disgust," &c. We may infer from this that there is something wrong in the expression. Some of the fifteen persons may, however, have been partly misled by not expecting to see an old man crying, and by tears not being secreted. With respect to another figure by Dr. Duchenne (fig. 49), in which the muscles of half the face are galvanized in order to represent a man beginning to cry, with the eyebrow on the same side rendered oblique, which is characteristic of misery, the expression was recognized by a greater proportional number of persons. Out of twenty-three persons, fourteen answered correctly, "sorrow," "distress," "grief," "just going to cry," "endurance of pain," &c. On the other hand, nine persons either could form no opinion or were entirely wrong, answering, "cunning leer," "jocund," "looking at an intense light," "looking at a distant object," &c.
As the upper lip is much drawn up during the act of screaming, in the manner just explained, the depressor muscles of the angles of the mouth (see K in woodcuts 1 and 2) are strongly contracted in order to keep the mouth widely open, so that a full volume of sound may be poured forth. The action of these opposed muscles, above and below, tends to give to the mouth an oblong, almost squarish outline, as may be seen in the accompanying photographs. An excellent observer, in describing a baby crying whilst being fed, says, "it made its mouth like a square, and let the porridge run out at all four corners." I believe, but we shall return to this point in a future chapter, that the depressor muscles of the angles of the mouth are less under the separate control of the will than the adjoining muscles; so that if a young child is only doubtfully inclined to cry, this muscle is generally the first to contract, and is the last to cease contracting. When older children commence crying, the muscles which run to the upper lip are often the first to contract; and this may perhaps be due to older children not having so strong a tendency to scream loudly, and consequently to keep their mouths widely open; so that the above-named depressor muscles are not brought into such strong action.