The Skeleton : Part 6

Physiology and Hygiene for Secondary Schools
by Francis M. Walters

(Page 19 of 28)

Treatment of Fractures. - A fractured bone always requires the aid of a surgeon, and no time should be lost in securing his services. In the meantime the patient should be put in a comfortable position, and the broken limb supported above the rest of the body. Though the breaking of a bone is not, as a rule, a serious mishap, it is necessary that the very best skill be employed in setting it. Any failure to bring the ends of the broken bone into their normal relations permanently deforms the limb and interferes with its use.

Dislocations and Sprains. - Dislocations, if they be of the larger joints, also require the aid of the surgeon in their reduction and sometimes in their subsequent treatment. Simple dislocations of the finger joints, however, may be reduced by pulling the parts until the bones can be slipped into position.

A sprain, which is an overstrained condition of the ligaments surrounding a joint, frequently requires very careful treatment. When the sprain is at all serious, a physician should be called. Because of the limited supply of blood to the ligaments, they are slow to heal, and the temptation to use the joint before it is fully recovered is always great. Massage judiciously applied to a sprained joint, by bringing about a more rapid change in the blood and the lymph, is beneficial both in relieving the pain, and in hastening recovery.

Summary. - The skeleton, or framework of the body, is a structure which is movable as a whole and in most of its parts. It preserves the form of the body, protects important organs, and supplies the mechanical devices, or machines, upon which the muscles act in the production of motion. The skeleton is adapted to its purposes through the number and properties of the bones, and through the cartilage and connective tissue associated with the bones. The places where the different bones connect one with another are known as joints, and most of these admit of motion. The preservation of the natural form of the skeleton is necessary, both for its proper action and for the health of the body.

Exercises. - 1. State the main purpose of the skeleton. What is the necessity for so many bones in its construction?

2. How may the percent of animal and of mineral matter in a bone be determined?

3. What properties are given the bones by the animal matter? What by the mineral matter?

4. Locate the bone cells. What is their special function?

5. State the plan by which nourishment is supplied to the bone cells in different parts of the bone.

6. Give the uses of the periosteum.

7. State the purpose of the Haversian canals. Of the canaliculus.

8. Give functions of the spinal column.

9. Name the different materials used in the construction of a joint and the purpose served by each.

10. Name four mechanical devices, or machines, found in the skeleton and state the purpose served by each.

11. Name one or more of the body machines not located in the skeleton.

12. Of what advantage is the peculiar shape of the lower jaw? Of the ribs? Of the bones of the pelvic girdle?

13. State the importance of preserving the natural form of the skeleton. How are unnatural curves produced in the spinal column?

14. How may slight deformities of the skeleton be corrected?

15. What different systems are employed in the body in the production of motion? What is the special function of each?

Practical Work

To obtain clear ideas of the form and functions of the bones, a careful examination of a prepared and mounted skeleton is necessary. Many of the bones, however, may be located and their general form made out from the living body. Bones of the lower animals may also be studied to advantage.

Experiments to show the Composition of Bone. - 1. Examine a slender bone, like that in a chicken's leg. Note that it resists bending and is difficult to break. Note also that it is elastic - that, when slightly bent, it will spring back.

2. Soak such a bone over night in a mixture of one part hydrochloric acid and four parts water. Then ascertain by bending, stretching, and twisting what properties the bone has lost. The acid has dissolved out the mineral matter.

3. Burn a small piece of bone in a clear gas flame, or on a bed of coals, until it ceases to blaze and turns a white color. Can the bone now be bent or twisted? What properties has it lost and what retained? What substance has been removed from the bone by burning?

Observation on the Gross Structure of Bone. - 1. Procure a long, dry bone. (One that has lain out in the field until it has bleached will answer the purpose excellently.) Test its hardness, strength, and stiffness. Saw it in two a third of the distance from one end, and saw the shorter piece in two lengthwise. Compare the structure at different places. Find rough elevations on the outside for the attachment of muscles, and small openings into the bone for the entrance of blood vessels and nerves. Make drawings to represent the sections.

2. Procure a fresh bone from the butcher shop. Note the difference between it and the dry bone. Examine the materials surrounding the sides and covering the ends of the bone. Saw through the enlarged portion at the end and examine the red marrow. Saw through the middle of the bone and observe the yellow marrow.

To show the Minute Structure of the Bone. - Prepare a section of bone for microscopic study as follows: With a jeweler's saw cut as thin a slice as possible. Place this upon a good-sized whetstone, not having too much grit, and keeping it wet rub it under the finger, or a piece of leather, until it is thin enough to let the light shine through. The section may then be washed and examined with the microscope. If the specimen is to be preserved for future study, it may be mounted in the usual way, but with hard balsam. Prepare and study both transverse and longitudinal sections, making drawings. The sections should be prepared from bones that are thoroughly dry but which have not begun to decay.

To show the Structure of a Joint. - Procure from a butcher the joint of some small animal (hog or sheep). Cut it open and locate the cartilage, synovial membrane, and ligaments. Observe the shape and surface of the rubbing parts and the strength of the ligaments.

D.C. Heath and Co. - Publishers
Original copyright 1909