Part 8 (1/2)

[Ill.u.s.tration: Fig. 30. The position a child naturally a.s.sumes when the seat is so high that the feet are not supported.]

134. What is said of the benches or chairs in a school-room? What is represented by fig. 29? By fig. 30? What is the effect when the lower limbs are not supported?

135. _Compression of the chest should be avoided._ In children, and also in adults, the ribs are very flexible, and a small amount of pressure will increase their curvature, particularly at the lower part of the chest, and thus lessen the size of this cavity. The lower ribs are united to the breast-bone, by long, yielding cartilages, and compression may not only contract the chest, but an unseemly and painful ridge may be produced, by the bending of the cartilages, on one or both sides of the sternum.

[Ill.u.s.tration: Fig. 31. A natural and well-proportioned chest.]

[Ill.u.s.tration: Fig. 32. A chest fas.h.i.+onably deformed.]

135. Why should compression of the chest be avoided? What is represented by fig. 31? By fig. 32?

136. Again, the cartilages on one side may be bent outward, while those on the opposite side are bent inward, thus forming a depression parallel with the sternum. In some instances, the anterior extremity of the lower ribs on each side are brought nearly or quite together.

In these instances, the movable extremities of the ribs are drawn down toward the haunch-bones, while the s.p.a.ce between the ribs is lessened.

All this may be effected by tight or ”snug” clothing. Therefore the apparel of a child should be loose, and supported over the shoulders, to avoid the before-mentioned evils. The same may be said of the clothing for adults.

137. _The erect position in sitting and standing should be a.s.siduously observed._ The spinal column, in its natural position, curves from front to back, but not from side to side The admirable arrangement of the bones, alternating with cartilages, permits a great variety of motions and positions; and when the spine is inclined to either side, the elasticity of its cartilages tends to restore it to its natural position. For this reason we may incline the spinal column in any direction for a short time, without danger of permanent curvature, if, afterward, the erect position is a.s.sumed.[4]

[4] Compare 1, 1, Fig. 28, with 2, 2, 2, Fig. 48.

138. But if a stooping position, or a lateral curved posture, is continued for a long time, the spinal column does not easily recover its proper position, for the compressed edges of the cartilages lose their power of reaction, and finally one side of the cartilage becomes thinned, while the other is thickened; and these wedge-shaped cartilages produce a permanent curvature of the spinal column. In a similar way, the student, seamstress, artisan, and mechanic acquire a stooping position, and become round shouldered, by inclining forward to bring their books or work nearer the eyes.

136. May simply ”snug” clothing compress the cartilages? How should the apparel of a child be worn? 137. In what direction does the spinal column, in its natural position, curve? What restores it to its natural position when curved laterally? 138. What is the effect if a lateral curved position of the spinal column is continued for a long time? 139. When one shoulder is elevated for a long time, what is the effect upon the spinal column?

139. Pupils, while writing, drawing, and sometimes while studying, frequently incline the spinal column to one side, in order to accommodate themselves to the desks at which they are seated. Often, these are higher than the elbow as it hangs from the shoulder while at rest. This att.i.tude elevates one shoulder while it depresses the other; consequently, the upper part of the spinal column is inclined toward the elevated shoulder, and the lower part is curved in the opposite direction, giving the form of the letter _S_ to the supporting column of the body.

[Ill.u.s.tration: Fig. 33. The table is of proper height, the position is correct, and the spinal column, 1, 1, is straight, while the shoulders are of equal height.]

What does fig. 33 represent?

_Experiment._ Let a pupil be placed at a desk or table with one elbow raised, as is frequently seen while writing, or at study, and observe the condition of the shoulder and spinal column in this position.

Place another pupil at a table no higher than the elbow when it hangs by the side while sitting, and observe the appearance of the shoulders and spinal column. By a comparison of the two att.i.tudes, the preceding remarks will be comprehended and appreciated.

[Ill.u.s.tration: Fig. 34. The table is too high, and the position is oblique and improper. The right shoulder is seen higher than the left, while the spinal column, 1, 1, exhibits three curves.]