Surgical experiences : the substance of clinical lectures / by Samuel Solly.

  • Samuel Solly
Date:
1865
Catalogue details

Licence: Public Domain Mark

Credit: Surgical experiences : the substance of clinical lectures / by Samuel Solly. Source: Wellcome Collection.

    22/676 (page 6)
    arising from tlie ilium, the sacral and the lumbar ver- tebrae, and tlie ribs, and inserted into the humerus. When these points, which are called the origin, are fixed, its action is to move the upper extremity backwards, and rotate it inwards. But suppose its insertion to be fixed on one side, the right arm, for instance, while the muscles attached to the spine on the left side remain in a relaxed state, then will the latissimus dorsi muscle act from the arm at the fixed point, and curve the lower portion of the spine to that side, and draw up the right hip. The action of both muscles from the arm upon the trunk is well seen if we lay hold of a bar above us, and draw the body up to it, when the arms are of course the fixed points, and the spine the movable one. From this illustration you will comprehend how all the muscles between the extremities and the spine are to be considered in connection with distorted spine : acting both from the spine on the arms and legs, and from the arms and legs on the spine. Also that, in order to move the arm on one side, the spine must be first fixed by muscles attached to the opposite side : just as the muscles which act from the os hyoides upon the lower jaw to open the mouth can only produce that effect while the os hyoides is fixed by those muscles which connect that bone to the sternum and scapula; for when it is not so fixed, the very same muscles raise the OS hyoides as in the act of deglutition. And although the spine is not so movable as the os hyoides, still the ligaments alone are not sufficient to prevent its being drawn out of the perpendicular line. In connection with the attachment and action of the spinal muscles, the surgical pathologist must study well the direction of the articulating surfaces of the vertebrae, in order to connect in his mind the influence which these muscles have over the joints of the spine. He observes in the cervical region that the articulating surfaces are nearly horizontal; consequently that this portion of the column must be dependent for its erect position upon the ligaments which run from one bone to the other, and to the numerous muscles which are