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A Description of the Human: Its Structure
A Description of the Human Its Structure Author:John Marshall Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: No. 2 -- The Muscles, Joints, and Animal Mechanics. The chief figure in this diagram displays the greater number of the superficial muscles of the human b... more »ody, and, on being studied with the subsequent description, will be found to illustrate most of the general statements therein contained respecting the Muscular System. Figs. 2, 3, and 4 represent examples, selected from the human frame, of the three kinds of mechanical arrangements denominated Levers. They are described after fig. 1. As the remaining figures, 5 to 8, relate to the structure of joints, a subject already partly illustrated in diagram No. 1, their description is intentionally put first in order. THE JOINTS. Figures 5 to 8. The peculiar mode in which the radius and ulna are connected together in the forearm is represented in fig. 6 ; whilst figs. 5, 7, and 8 show respectively the interior of the shoulder-, hip-, and knee-joints. In the three last-mentioned figures, the joints are supposed to be laid open by cutting through the bones which enter into their formation, so as to obtain the view called a Section. The cut surfaces of the bones show the difference between the outer dense or compact bony tissue, and the inner, more open, spongy, or cancellated texture, in which the blood-vessels and marrow are placed. The surfaces of the bones which enter into the joints are seen to be shaped so as to fit one to the other, and, moreover, to be covered with a thin closely-adherent layer of cartilage quite smooth on its free surface. It will be observed that in these figures the bones are drawn a little asunder, in order to display more distinctly the cavities of the joints, marked C, which, in each case, are seen to be limited by the synovial membrane connecting the two bones, and attaching itself ne...« less