DIAGNOSTIC PRINCIPLES 47 



deposits, the eoiulitiou may be such that prompt recovery will 

 follow proper treatment. In the examination of an exostosis of 

 the tarsus, it is particularly important to determine the exact 

 location of the exostosis — whether or not the spavin involves 

 the ti])ial tarsal (astragulus) ])one very near its tibial articular 

 portions. Obviously, if articular surfaces of joints are involved, 

 comjilete recovery cannot result despite the most skillful atten- 

 tion given the subject. 



Passive Movements. 



Wherever it is possible to gain the confidence of a tractable 

 animal to the extent that it will relax the structures sufficiently 

 to nuike possible passive movement of affected parts, much is 

 to be learned as a result of such manipulation. By this method 

 one may differeiitiate true crepitation, false crepitation, luxation 

 and inflammation of ligaments that have been injured, as in 

 sprains of such structures in the phalangeal region. 



True crepitation is recognizable by the characteristic vibra- 

 tion which is interjireted by tactile sense. It is possible to rec- 

 ognize fracture by the use of other methods — auscultation, tun- 

 ing fork tests, etc., but in ordinary veterinary practice one must 

 rely upon the sense of touch for recognition of crepitation. 



Where pain is not so great tliat relaxation of parts does not 

 occur, one can, by gently moving an extremity in various di- 

 rections — as in flexion, extension and lateral motion as well as by 

 rotation — cause to be manifested this peculiar grating, — the 

 friction of newly broken bone. This is known as true crepitation. 

 Where the subject, suffering phalangeal fracture, manifests 

 evidence of pain due to tensing the structures abinit a fractured 

 part, one may anesthetize the parts by using a1)0ut two cubic' 

 centimeters of a two per cent, solution of cocain upon the plantar 

 nerves, proximal to the fracture. It is perhaps l)est to deposit 

 the cocain solution by means of two hypodermic punctures at 

 different points along the course of each nerve, though closely 

 situated to one another, thereby making more sure of the so- 

 lution actually contacting the nerve. In some multiple frac- 

 tures of the first or second phalanx this is quite necessary; 

 otherwise, pain produced by passive manipulation causes the 



