Part 7 (2/2)

[Ill.u.s.tration: Fig. 28. 1, 1, The spinal column. 2, The skull. 3, The lower jaw. 4, The sternum. 5, The ribs. 6, 6, The cartilages of the ribs.

7, The clavicle. 8, The humerus. 9, The shoulder-joint. 10, The radius.

11, The ulna. 12, The elbow joint. 13, The wrist. 14, The hand. 15, The haunch-bone. 16, The sacrum. 17, The hip-joint. 18, The thigh-bone. 19, The patella. 20, The knee-joint. 21, The fibula. 22, The tibia. 23, The ankle-joint. 24, The foot. 25, 26, The ligaments of the clavicle, sternum, and ribs. 27, 28, 29, The ligaments of the shoulder, elbow, and wrist. 30, The large artery of the arm. 31, The ligaments of the hip-joint. 32, The large blood-vessels of the thigh. 33, The artery of the leg. 34, 35, 36, The ligaments of the patella, knee, and ankle.]

_Note._ Let the pupil, in form of topics, review the anatomy and physiology of the bones from fig. 28, or from anatomical outline plates No. 1 and 2.

CHAPTER VII

HYGIENE OF THE BONES.

129. _The bones increase in size and strength by use, while they are weakened by inaction._ Exercise favors the deposition of both animal and earthy matter, by increasing the circulation and nutrition in this texture. For this reason, the bones of the laborer are dense and strong, while those who neglect exercise, or are unaccustomed to manual employment, are deficient in size, and have not a due proportion of earthy matter to give them the solidity and strength of the laboring man.

_Observation._ The tendons of the muscles are attached near the extremities of the bones. Exercise of the muscles increases the action of the vessels of that part to which the tendons are attached, and thus increases the nutrition and size of this portion of the bone.

Hence the joints of an industrious mechanic or farmer are larger than those of an individual who has not pursued manual vocations.

130. _The gelatinous bones of the child are not so well adapted for labor and severe exercise as those of an adult._ 1st. They are liable to become distorted. 2d. They are consolidated by the deposition of earthy material before they are fully and properly developed. If a young animal, as the colt, be put to severe, continued labor, the deposition of earthy matter is hastened, and the bones are consolidated before they attain full growth. Such colts make small and inferior animals. Similar results follow, if a youth is compelled to toil unduly before maturity of growth is attained. On the other hand, moderate and regular labor favors a healthy development and consolidation of the bones.

129-148. _Give the hygiene of the bones._ 129. What effect has exercise upon the bones? What effect has inaction? Why are the joints of the industrious farmer and mechanic larger than those of a person unaccustomed to manual employment? 130. Give the first reason why the bones of the child are not adapted to severe exercise. The second reason.

131. _The kind and amount of labor should be adapted to the age, health, and development of the bones._ Neither the flexible bones of the child nor the brittle bones of the aged man are adapted, by their organization, to long-continued, and hard labor. Those of the one bend too easily, while those of the other fracture too readily. In middle age, the proportions of animal and earthy matter are, usually, such as to give the proper degree of flexibility, firmness, and strength for labor, with little liability to injury.

132. _The imperfectly developed bones of the young child will not bear long-continued exertions or positions without injury._ Hence the requisitions of the rigid disciplinarian of schools, are unwise when he compels his pupils to remain in one position for a long time. He may have a ”quiet school;” but, not unfrequently, by such discipline, the const.i.tution is impaired, and permanent injury is done to the pupils.

133. _The lower extremities, in early life, contain but a small proportion of earthy matter_; they bend when the weight of the body is thrown upon them for a long time. Hence, the a.s.siduous attempts to induce children to stand or walk, either naturally or artificially, when very young, are ill advised, and often productive of serious and permanent evil. The ”bandy” or bow legs are thus produced.

What effect has moderate, regular labor upon the growing youth? 131.

What remark respecting the kind and amount of labor? At what age are the bones best fitted for labor? 132. What effect has long-continued exertions or positions on the bones of a child? What is said of the requisitions of some teachers, who have the famed ”quiet schools”?

133. Why should not the child be induced to stand or walk, either naturally or artificially, at too early an age?

134. _The benches or chairs for children in a school-room should be of such a height as to permit the feet to rest on the floor._ If the bench is so high as not to permit the feet to rest upon the floor, the weight of the limbs below the knee may cause the flexible bone of the thigh to become curved. The child thus seated, is inclined to lean forward, contracting an injurious and ungraceful habit. Again, when the feet are not supported, the child soon becomes exhausted, restless, and unfit for study. In the construction of a school-room, the benches should be of different heights, so as to be adapted to the different pupils, and they should also have appropriate backs.

[Ill.u.s.tration: Fig. 29. The position a.s.sumed when the seat is of proper height, and the feet supported.]

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