and in dislocation of the shoulder; and either of them may be
separated by muscular contraction or by direct violence.

_Clinically_ all these injuries are difficult to diagnose with
accuracy, and, without the use of the X-rays, it is impossible in many
cases to go further than to say that a fracture exists above the level
of the surgical neck. Fracture of the anatomical neck is attended with
little deformity beyond slight flattening of the shoulder and
sometimes slight shortening of the upper arm.

When the _great tuberosity_ is torn off, considerable antero-posterior
broadening of the shoulder may be recognised by grasping the region of
the tuberosities between the fingers and thumb. Crepitus can be
elicited on rotating the humerus. At the same time it will be
recognised that the tuberosity does not move with the shaft. Firm
union, with considerable formation of callus and some broadening of
the shoulder, usually results, but the usefulness of the joint is not
necessarily impaired. There may, however, be prolonged stiffness and
impaired movement from adhesion; or pain and crackling in the joint
may result from arthritic changes like those of arthritis deformans.

_Treatment._--These fractures are treated on the same lines as
fracture of the surgical neck of the humerus.

The combination of fracture of the upper end of the humerus with
dislocation of the shoulder has already been referred to.

FRACTURE OF THE SHAFT OF THE HUMERUS

Fractures occurring in the shaft of the humerus between the surgical
neck and the base of the condyles may, for convenience of description,
be divided into those above, and those below, the level of the deltoid
insertion--the majority being in the latter situation.

Direct violence is the most common cause of these fractures, but they
may occur from a fall on the elbow or hand; and a considerable number
of cases are on record where the bone has been broken by muscular
action--as in throwing a cricket-ball. Twisting forms of violence may
produce spiral fractures.

The fracture is usually transverse in children and in cases in which
it is due to muscular action. In adults, when due to external
violence, it is usually oblique, the fragments overriding one another
and causing shortening of the limb. The displacement depends largely
on the direction of the force and the line of fracture, but to a
certain extent also on the action of muscles attached to the
fragments. Thus, in fractures