12. The signs which characterize a luxation of the radius forward,
are, 1st, The constant pronation of the limb: 2dly, An inability in it
to assume the state of supination, and even severe pains arising from
attempting it: 3dly, A protuberance larger than common, formed behind,
by the small head of the ulna passing through the capsule: 4thly, The
end of the radius being situated more anteriorly than natural: 5thly,
The constant adduction, and almost constant extension of the wrist:
6thly, The semiflexion of the fore-arm, and very often of the fingers:
this position is generally assumed by the fore-arm, in affections of
the bones that form it, and, in the present case, cannot be changed
without considerable pain: 7thly, A swelling more or less extensive,
which sometimes appears around the articulation, at the moment of
the accident, and which never fails to occur afterwards, unless the
reduction be immediately effected. This occurrence may conceal the
state of the articulation, and make the accident be considered, at
first sight, as a sprain, as Desault witnessed in certain cases, where
the disease had been mistaken by the surgeons who were first called to
the persons injured. It is easy to conceive of the sad consequences of
this mistake, which, by preventing any effort at reduction, gives the
articular surfaces time to form adhesions, and thus oftentimes renders
the mischief irreparable.
13. If to these signs be added, the severe pains experienced by the
patient, the circumstances of the fall, in which the fore-arm is
violently drawn into a state of pronation, we will have a view of every
thing that can here aid the practitioner in his diagnosis.
14. Most of the foregoing signs, taken in the opposite sense, would
characterize a luxation of the radius backward, should it occur: such,
for example, as a forced supination of the limb, an inability as to
pronation, the pains that would result from this movement if performed
by force, the tumour formed anteriorly by the extremity of the ulna,
the posterior situation of the large head of the radius, and the
abduction of the wrist.
15. The dead body, in which Desault observed this kind of displacement
(9), being dissected with care, exhibited in the articular parts, the
following diseased state. The tendons of the flexor muscles, pushed
outwards, adhered to one another and to the skin; a substance of a
cellular texture filled up the sigmoid cavity of the radius, and
occupied the place of the cartilage which naturally invests it: the
inter-articular ligament, which passes between the ulna and the os
pyramidalis, scarcely touched the head of the ulna, having followed the
radius backwards; and the head of the ulna, situated before the sigmoid
cavity of the radius, rested on one of the ossa sesamoidea, to which it
was attached by a capsular ligament.
§ V.