of
the part, as the elbow; while others have no movement, as the bones of
the head in the adult.

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Explain fig. 27. 128. Describe the variety of movements in the
different joints.

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[Illustration: 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