The most frequent abnormality of the upper extremity is polydactylism. If there is but a rudimentary finger attached loosely by a pedicle which does not contain any phalanges at all, removal is simple.
In Case 1, illustrating a boy of four months, the supernumerary digit, as shown by the skiagraph, contained no bone-tissue. (Fig. 1.) Removal was naturally easy. In the same case there was a partial fusion of the third and fourth metacarpal bones, a condition which would not have been diagnosed without the Roentgen rays.
Case 2 represents the more complicated type of true supernumerary digits articulating with each other. There was also a supernumerary digit attached to the little toe. (Fig. 2.)
Case 3 shows a true supernumerary phalanx attached to the thumb and articulating with the first metacarpal bone. It is nearly as large as the normal phalanx and possesses a well-developed nail. It is held