Holden's human osteology : comprising a description of the bones with delineations of the attachments of the muscles, the general and microscopic structure of bone and its development / edited by Charles Stewart and R.W. Reid.

  • Holden, Luther, 1815-1905.
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: Holden's human osteology : comprising a description of the bones with delineations of the attachments of the muscles, the general and microscopic structure of bone and its development / edited by Charles Stewart and R.W. Reid. Source: Wellcome Collection.

    27/508 (page 9)
    sure, or form arches, thus combming the gi-eatest strength and elasticity with Hghtness. A beautiful example of this is seen in the section of the cancellous tissue of the thigh-bone (Plate I.)- At the lower part, towards the knee, the layers run vertically— that is, m the direction of the axis of the shaft, this being the line of pressui-e when the body is erect. But in the neck of the thigh-bone the layers are arranged in decussating curves like Gothic arches, one within the other, and sustain with the greatest mechanical advantage the weight transmitted on to the heads of the thigh-bones. (Norm. Hum. Ost., Nos. 211 to 222.) Cancellous Tissue: Properties.—Though SO light and spongy, the cancellous tissue is able to support a great weight without giving way. We may form some idea of its strength from the following experiment: ^ A cubic inch of cancellous texture was taken from the lower end of the femm-, and placed with its principal layers upright. Four cwt. was then placed upon it, but it did not give way in the least. Six cwt. made it sink half an inch. Yet the cubic inch of bone itself did not weigh more than 54 grains. Not only is cancellous tissue strong as well as hght, but it possesses another advantage—that of diminishing shocks. When a ball of ivory strikes another, as in the game of billiards, the whole force of the shock is trans- mitted from one to the other; but let a ball made of the can- cellous tissue be interposed, and then see how the shock will be broken. This property of diminishing shocks is of course greater when the bone is in its natiiral state and filled with marrow. The spaces formed by the cancellous tissue vary in size and shape, ]jut freely communicate with each other, and with the holes on the surface of the bones. This is easily proved by boring a hole at one end of a bone, and pouring mercury into it; we shall find that the mercury will run out freely through the natural holes at the other end. iviarrow, Yellow.—The interior of the shaft of a long bone is filled with yellow marrow; a substance composed almost en- tirely of fat (9G per cent.) ; that is, in bones that are healthy.