Essays and observations on natural history, anatomy, physiology, psychology, and geology / by John Hunter, being his posthumous papers on those subjects, arranged and revised, with notes ; to which are added the introductory lectures on the Hunterian collection of fossil remains delivered in the theatre of the Royal College of Surgeons of England, March 8th, 10th and 12th, 1855 / by Richard Owen.
- John Hunter
- Date:
- 1861
Licence: Public Domain Mark
Credit: Essays and observations on natural history, anatomy, physiology, psychology, and geology / by John Hunter, being his posthumous papers on those subjects, arranged and revised, with notes ; to which are added the introductory lectures on the Hunterian collection of fossil remains delivered in the theatre of the Royal College of Surgeons of England, March 8th, 10th and 12th, 1855 / by Richard Owen. Source: Wellcome Collection.
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![having a number of joints or movements [of parts of the skeleton] on each other, have so many fixed points; the larger portion becoming the fixed point to the smaller; until, at last, the whole body has its fixed point, or point of resistance to move upon. Animals that move upon the earth, have that for their fixed point; birds that fly have the air for their fixed point; and fishes have the water for their fixed point. Besides these general fixed points of motion for the whole animal, each animal has a fixed point within itself from which the parts of the body take their principal motion. In the human body this fixed point seems to be in the joints of the thigh-bones; and being in the middle of the body, it must be common to the extremities; therefore we see that the trunk either moves on the legs, or the legs on the trunk. Besides this there are as many fixed points as there are joints; so that the body is to be looked upon as a chain of joints whose general centre of motion is in the joints of the thighs; but each has its centre of motion, which is always on that side next to the general. The greater the motion in any joint, the less nice it is; therefore, where correctness and nicety is wanted, the parts of motion are divided into smaller movements; as, for instance, the bones of the fingers become shorter and shorter towards their terminations. Of the Spine.—The spine in animals is that which is the basis of the whole body, on which everything is built. It gives support to the whole, and may be said to be like the keel of a ship—the first thing laid down, from which the whole superstructure is to arise. Prom its great length, it is necessary to have motion within itself; and, as it would be improper for it to bend at one part sufficiently for the required motion, more especially on account of the ribs and viscera, it is made up of a number of bones, that it might have an easy motion through the whole: this also protects the spinal marrow from being hurt by too quick a bend. The other joints have no parts save for their simple motion; but the trunk has a great many, which prevents such motion. The spine is straight in a fore view, because the two sides of the body are similar parts; but the back and fore parts not being similar, the spine is bent accordingly, to be able to support the different weights applied to it. However, this is observable principally in the human subject, owing to his erect position. -That part of the spine to which the other bones of the pelvis are attached [the sacrum], is commonly nearly in the same line with the rest of the chain of bones ; although, in most, it is a little bent so as to give space to the pelvis; but in the human it is thrown further back, in order that the thigh-bones might be brought perpendicularly under the spine, and at the same time the](https://iiif.wellcomecollection.org/image/b21182656_0407.jp2/full/800%2C/0/default.jpg)
