[CHAPTER XXXIX.]
MOUNTING A LARGE DISARTICULATED SKELETON.
It will be well for anyone who intends to mount a large skeleton, if he has not already a fair knowledge of osteology, to take some book which contains a description of the skeleton, for example, of the domestic cow, and familiarize himself with the names of the various bones and the different anatomical terms used in describing them. In fact it is next to impossible to describe the process of mounting a skeleton without making use of quite an array of technical terms.
In order to make our description of this intricate process as clear as possible, we will choose as our typical subject the skeleton of an American bison, and go through with it in detail, aided by an abundant supply of illustrations. We of course assume that the macerating, cleaning, and bleaching has been done.
In mounting a disarticulated skeleton, begin with the vertebral column as the key to the situation. It is, in point of fact, the keel upon which the whole structure is to be built. The vertebræ should be arranged, each in its place, and, then they should be numbered with pen and ink on the anterior articulating surface of the body of each one, beginning with the first vertebra in front of the sacrum. This vertebra (the last lumbar) should be marked No. 1, the next in front No. 2, and so on to the axis.
The next step consists in boring two holes through the sacrum from its under surface (Fig. 73, a, a) to its anterior articulating surface (b, b), and these holes should be continued on through the body of each of the succeeding vertebrae to the axis. They should come out underneath that vertebra (the axis), where the wires which pass through all these holes are afterward to be twisted together. The holes should be somewhat larger than the brass wires which are to pass through them.
It is necessary to mark the place for starting the drill into the posterior surface of each vertebra by fitting two articulating surfaces together, and passing the drill through the holes already made. The points at which the drill should come out on the anterior surface of a vertebra should be marked with a lead pencil. The beginner will find some difficulty in making the drill come through at precisely the right spot. The greatest difficulty will be experienced in getting these holes through the cervical vertebrae.
When the axis is reached, bore the holes so that they will come out underneath, about half way between each extremity of the vertebra, and about three-fourths of an inch apart.
It is just as well to now bore the holes through which the wires which fasten the axis and atlas together are to pass, though these need not be actually united until the remainder of the spinal column has been, articulated. The wires uniting the atlas and axis are smaller than those passing through the spinal column. The holes for these wires are made by boring two of them through each of the two surfaces by which the axis articulates with the atlas. These holes should come out underneath the axis. Then, placing the axis and atlas together, mark on the atlas the places through which the holes are to pass by running the drill through each of the holes already made.