It is only in cases where the fracture is situated so high as an inch and a half, or more, above the joint, that any abnormal ap proximation of the bones towards each other, and ultimate obliteration of the interosseous interval is to be dreaded.
Although therefore, as a result of Colles' fracture, we observe the forearm assume, near the wrist-joint, a cylindroidal form, there may be no real narrowing whatever, but the ap pearance of it may be attributed rather to an increase, in the antero-posterior diameter of the region of the wrist, than to any real diminution which occurs transversely.
Malgaigne has, however, adduced an example to explain how, in certain rare cases, a diminu tion of the transverse diameter of the forearm may occasionally take place, and by the action of the pronator quadratus not on the inferior, but on the upper fragment of the radius. (fig. 932.) It is said by some, that crepitation, caused by the movements of the fragments of the broken radius on each other, can always be elicited, and that this sign is diagnostic of fracture ; moreover, that the deformity is easy to reduce by extension, but liable to return when the extending force is removed. Such observations, no doubt, may sometimes be made with truth. For our own parts, we do not think that crepitation can, except in a very few cases, be elicited in Colles' fracture of the radius. We have found it to be an injury attended with a deformity which can, it is true, be removed by extension, but our experience corresponds with that of Sir A.
Diagnosis.— In many cases, a fracture of the radius in the immediate vicinity of the wrist joint is attended with so much deformity, and accompanied with such characteristic appear ances, that the observation of Pouteau appears well founded, that it can be recognised at the first "coup d'ceil ;" but on the other hand, there are some cases in which very little ex ternal evidence of any fracture can, without careful examination, be detected. The un dulating curve, which has been compared to that represented by a silver fork, cannot exist without fracture, and the elevation from the level of the back part of the radius of the common extensor tendons is another feature, which we believe with Velpeau to be peculiar to fracture ; we know that in the normal state the tendons of the extensor carpi radialis longior and brevior remain applied as longi tudinal bands, lying flat on the posterior surface of the radius, and no interval whatever exists between these two bands and the back part of this bone near to the wrist. Now, when there is a fracture of the radius here, this bone is rendered somewhat concave on its posterior surface, and these tendons must, of necessity, abandon the bony surface, and be raised up several lines from it, so as to repre sent a cord, more or less tense, but easy to depress. If, for example, the hand of the patient being a little flexed, the surgeon in examining these cases, places his finger or thumb three or four lines above the level of the wrist-joint, on the posterior surface, and near to the external border of the radius, he will, if fracture exist, recognise beneath the skin the tense cord, and perceive that it can be depressed even to the posterior surface of the radius, from which it had been manifestly elevated. This last is a test upon Velpeau specially relics.
Upon the subject of Diagnosis of this fracture of the carpal end of the radius, Dr. Colles remarks,—" the facility with which the surgeon can move the ulna backwards and forwards, dots not furnish him with any useful help in his diagnosis as to the true notion of the injury. Moreover, when he moves his fingers along the anterior surface of the radius, he finds it more full and prominent than is natural ; a similar examination of the posterior surface of this bone, induces him to think that a depression exists about an inch and one half above its carpal extremity. He
now may expect to find satisfactory proofs of a fracture, of the radius at this spot. For this purpose he attempts to move the broken pieces of the hone in opposite directions, but, the patient is by this examination subjected to considerable pain, yet neither crepitus, nor a yielding of the bone at the seat of fracture, nor any other positive evidence of the ex istence of such an injury is thereby obtained. At last," adds Dr. Colles, "after many un successful trials, I hit upon the following simple method of examination, by which I was enabled to ascertain that the symptoms above enumerated actually arose from a frac ture of the lower extremity of the radius — let the surgeon apply the fingers of one hand to the seat of the suspected fracture, and locking the other hand in that of the patient, make a moderate extension, until he observes the limb restored to its natural form. As soon as this is affected, let him move the patient's hand backward and forward, and he will, at every such attempt, be sensible to a yielding of the fractured end of the bone, and this to such a degree as to remove all doubt from his mind." I have already stated that sometimes the fracture may exist without being accompanied by any appreciable displacement of the bones. The patient complains of a severe pain in the region of the wrist, when pressure is made on the broken part, and also when the fore arm is moved. These are the only symptoms which exist, (if we except a slight swelling, particularly observable on the anterior surface of the wrist,) so that one would be tempted to believe that there was only a simple sprain existing. lf, however, we make pressure on the line of the articulation, we do not cause the patient any pain, which we should do, if the symptoms arose from a sprain, while if the same degree of pressure be made a few lines above the joint, the pain is very severely felt. Now, if we place a thumb on the radius behind, in the presumed seat of fracture, and make the effort to bend the wrist at this part, so as it were to make the forearm here form an angle on itself, salient anteriorly ; if the angle be thus formed, we hereby obtain a pathognomonic sign of the fracture ; and a comparison of the two wrists submitted equally to this experiment, puts the matter beyond all doubt.* Fractures of the lower extremity of the radius are generally looked upon as serious injuries. if this fracture has been mistaken for a sprain, or luxation, or abandoned to nature, according to Dupuytren, very serious changes ensue. "The forearm, in the region of the wrist, instead of presenting a surface flattened anteriorly, will assume a cylindroidal form. The movement of pronation and supination will be lost, an edematous swell ing of the soft parts will continue ; the arti culation remains immovable for a consi derable time, and, if a rupture of the lateral ligament of the inferior radio-cubital articula tion, or fracture of the styloid process of the ulna be superadded to the fracture of the lower extremity of the radius, we may see continue for life the abnormal mobility of the two bones on each other." Mr. Diday, of Paris, has gone further, and asserted that these consequences of fracture of the radius, above alluded to, are often observed, in spite of all kinds of treatment, and of bandages, which modern surgery has suggested.