DISCOVERY 



155 



be borno upon the limb. The side-bars are of just such 

 a length that when the man sits on the upper end, a 



[Reproduced by permission of the Oxford Medical Publications.) 



small part (or none if desired) of his weight is trans- 

 mitted through his own leg to the heel of the boot, 

 and the splint prevents any shortening of the limb. 

 Transmitted pressure, thus provided, is found to exert 

 a very beneficial effect on the rate of bone-repair : 

 for even a healthy bone becomes fragile if it is not 

 permitted to withstand the stresses for which it is 

 constructed. Elmslic^ in London, and more fecently 

 Els of Bonn, have published cases in which bonc-graft> 

 have themselves grown to a much larger size from 

 the effect of transmitted stresses.- It is of advantage, 

 then, to the fractured bone, as well as a convenience to 

 the patient, that he should get about at an early datr 

 in a caliper spUnt. It is of great use for similar 

 reasons — the partial maintenance of natural function- 

 — in other conditions besides fractures. 



The treatment of limbs after injury to nerves ha- 

 fallen within the scope of the orthopaedic surgeon on 

 account of the deformities which follow the consequent 



' See reference No. 3 at end of article, 



2 Bond, of Leicester, and Huntingdon, of California, published 

 the first cases in 1905. 

 » See Fig 3. 



unbalanced muscular forces,' and on account of the 

 need for special treatment to the muscles put out of 

 action by nerve injur}'. Apart from repair of the 

 nerve, a grave problem is presented by the injury 

 inflicted on a muscle by complete loss of activity, the 

 wasting of muscles being in these cases extreme. Nor 

 was it (till recently perhaps) a simple matter to cir- 

 cumvent this secondary effect of nerve injury. Muscles 

 which have been cut off from the central nervous system 

 show a series of changes which has been known as the 

 " reaction of degeneration," a change which, it has 

 been discovered, is in reality an increased minimum 

 duration of the effective electrical stimulus to con- 

 traction. A normal muscle is sensitive to electrical 

 stimuli of very short duration. If one (electrical) pad 

 is placed on the " motor point "of an arm muscle, and 

 the other terminal moved about over the belly of the 

 muscle until the optimum position is found, an impulse 

 lasting only tjxJjju second of a loo-volt potential 

 will cause a definite contraction. But after six weeks' 

 deprivation of impulses through its nerve, this muscle 



,\I-;I'h;tiijn splint for u?e wiitx tiii; .\i<.m (..xnni iT, c_>\ving 



TO NERVE INJURY, BE LIFTED FROM THE SIDE. 

 iRt produced by permission of the Oxford Medical Publications.) 



