nes are not always
essential to a good functional result.

* * * * *

As most of the remaining signs are common to all the lesions from
which fractures have to be distinguished, their diagnostic value must
be carefully weighed.

_Interference with Function._--As a rule, a broken bone is incapable
of performing its normal function as a lever or weight-bearer; but
when a fracture is incomplete, when the fragments are impacted, or
when only one of two parallel bones is broken, this does not
necessarily follow. It is no uncommon experience to find a patient
walk into hospital with an impacted fracture of the neck of the femur
or a fracture of the fibula; or to be able to pronate and supinate the
forearm with a greenstick fracture of the radius or a fracture of the
ulna.

_Pain._--Three forms of pain may be present in fractures: pain
independent of movement or pressure; pain induced by movement of the
limb; and pain elicited on pressure or "tenderness." In injuries by
direct violence, pain independent of movement and pressure is never
diagnostic of fracture, as it may be due to bruising of soft tissues.
In injuries resulting from indirect violence, however, pain localised
to a spot at some distance from the point of impact is strongly
suggestive of fracture--as, for example, when a patient complains of
pain over the clavicle after a fall on the hand, or over the upper end
of the fibula after a twist of the ankle. Pain elicited by attempts to
move the damaged part, or by applying pressure over the seat of
injury, is more significant of fracture. Pain elicited at a particular
point on pressing the bone at a distance, "pain on distal
pressure,"--for example, pain at the lower end of the fibula on
pressing near its neck, or at the angle of a rib on pressing near the
sternum,--is a valuable diagnostic sign of fracture. When nerve-trunks
are implicated in the vicinity of a fracture, pain is often referred
along the course of their distribution.

_Localised swelling_ comes on rapidly, and is due to displacement of
the fragments and to haemorrhage from the torn vessels of the marrow
and periosteum.

_Discoloration_ accompanies the swelling, and is often widespread,
especially in fracture of bones near the surface and when the tension
is great. It is not uncommon to find over the ecchymosed area,
especially over the shin-bone, large blebs containing blood-stained
serum. In fractures of deep-sea