out the middle of the shaft, the proximal end of the distal fragment
projecting towards the dorsum. Apart from this there is little
deformity, as the adjacent metacarpals act as natural splints and tend
to retain the fragments in position. A sudden sharp pain may be
elicited at the seat of fracture on making pressure in the long axis
of the finger; and unnatural mobility and crepitus may usually be
detected. These fractures are readily recognised by the X-rays. Firm
union usually results in three weeks.

The shaft of the _metacarpal of the thumb_ is frequently broken by a
blow with the closed fist. The fracture is usually transverse, and
situated near the proximal end of the shaft; frequently it is
comminuted, and in some instances there is a longitudinal split.

_Treatment._--When the fracture is transverse, and especially when it
implicates the middle or ring fingers, the most convenient method is
to make the patient grasp a firm pad, such as a roller bandage covered
with a layer of wool, and to fix the closed fist by a figure-of-eight
bandage. In this way the adjoining metacarpals are utilised as side
splints. Active and passive movements must be carried out from the
first, and the bandage may be dispensed with at the end of a week or
ten days.

In oblique fractures with a tendency to overriding of the fragments,
especially in the case of the index and little fingers, it is
sometimes necessary to apply extension to the distal segment of the
digit, by means of adhesive plaster, to which elastic tubing is
attached and fixed to the end of a bow splint, reaching well beyond
the finger-tips (Fig. 52). This should be worn for a week or ten days.

[Illustration: FIG. 52.--Extension apparatus for Oblique Fracture of
Metacarpals.]

#Bennett's Fracture of the Base of the First Metacarpal
Bone.#--Bennett of Dublin described an injury of the thumb which,
although comparatively common, is often mistaken for a sub-luxation
backward of the carpo-metacarpal joint, or a simple "stave of the
thumb." It consists in an "oblique fracture through the base of the
bone, detaching the greater part of the articular facet with that
piece of the bone supporting it which projects into the palm" (Fig.
53). We have frequently observed the fracture extend for a
considerable distance along the palmar aspect of the shaft.

[Illustration: FIG. 53.--Radiogram of Bennett's Fracture of Base of
Metacarpal of Right Thumb.]

It usually results from