Amputation by a long single flap, either dorsal or palmar, may be rendered necessary by accident. The palmar one of the two is preferable; indeed, rather than trust for a covering to the thin skin of the back of the hand, with its numerous tendons, it is better to amputate an inch or two higher up through the fore arm. The following amputation by external flap has been described (so far as I can discover, for the first time) by Dr. Dubrueil, in his work on operative Surgery:[26]--"Commencing just below the level of the articulation, while the hand is pronated, the surgeon makes a convex incision, beginning at the junction of the outer and middle thirds of the arm behind, reaching at its summit the middle of the dorsal surface of the first metacarpal, and terminating in front just below the palmar surface of the joint, again at the junction of the outer and middle thirds of the breadth of the arm. This flap being raised, the wrist is disarticulated, beginning at the radial side. A circular incision finishes the cutting of the skin." (Figs. III. and IV.) [Illustration: FIG. III.[27]] [Illustration: FIG. IV.[27]] AMPUTATION THROUGH THE FORE-ARM.--The method of operating must, in the fore-arm, depend a good deal upon the part of the arm where you require to amputate, the muscularity of the limb, and the condition of the skin and subcutaneous cellular tissue. It must be remembered that a section of the fore-arm involves two bones, not, like the tibia and fibula, on a constant permanent relation in position to each other, but which rotate one upon another to an amount which varies with the part of the limb divided, and which rotation is a very important element in the future usefulness of the stump; again, that two sets of muscles occupy, one the back, the other the front of the limb, that these two are unequal in size, and that the outer sides or rather edges of each bone are subcutaneous; again, that these sets of muscles are comparatively fleshy in the upper two-thirds of the limb, and almost entirely tendinous in the lower third. Remembering these points, we find that certain things require our attention, and certain difficulties are present in amputation of the fore-arm, from which amputation of the arm, with its single bone and copious muscular covering on all sides, is completely free. Thus our flaps in the fore-arm must be antero-posterior; lateral flaps are an impossibility. Great care is requisite to cut them at all equal, from the inequality of the muscles on the two sides. In the lower third we cannot obtain available muscular flaps. Lastly, care must be taken lest, from the ever-varying relations of the two bones to each other in the varying positions of the limb, the surgeon mistake their position and pass his knife between them.