Royal Army Medical Corps training pamphlet / War Office.

Date:
1944
Catalogue details

Licence: Public Domain Mark

Credit: Royal Army Medical Corps training pamphlet / War Office. Source: Wellcome Collection.

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    months the new individual is ready to be born. In this short | period every human being develops from a _ single-celled animal (the fertilized ovum) into a body composed of millions of highly specialized cells arranged in bones, muscles, nerves, glands and other tissues. Throughout childhood this infant body develops, physically and mentally, into the adult. The structure of the adult body can now be studied in more detail. CET AS Trees THE SKELETON 13. The adult skeleton consists of 206 bones, of various shapes and sizes, held together by bands or ligaments. Some of the joints between bones allow a wide range of movement, while others allow very little. ‘ The bones determine the general shape and proportions of © the body (Fig. 6). They form levers on which the muscles act to move the limbs or other parts of the body from one position to another. Some of them also provide protection for important organs. 14. Classes of bone.—Bones are Maia NaN classified according to shape, as follows :— Example ~ Long ee .. Thigh-bone Short eee ye eet DOne. Tiater: es .. Shoulder-blade. Irregular... .. Hip-bone. 15. Structure of bone.—Bones are composed of animal matter to give resilience, and lime to make them hard. Bone is stronger than oak, but lighter. In old people the proportion of lime increases, which makes their bones more brittle and so more readily fractured. The parts of bones which form joints are covered by gristle or cartilage. Elsewhere they are clothed with periosteum, a thin fibrous sheath, which contains blood- vessels and nourishes the bone. The shaft of a long bone is a tube of solid compact bone (Fig. 7). The medullary cavity in the centre contains yellow bone-marrow and numerous blood-vessels. At the ends of long bones, and throughout short bones, the structure is cancellous—t.e. it is made of fine interlacing laths of bone forming a network with minute spaces in between. This