780 l'\ i:\I.YSIS OF RADIAL NERVE. 



after exertion on sofl or uneven ground. When the lameness diminishes 

 after having long existed, the animals instinctively adopt a peculiar 

 way of moving. In stepping out they slide the foot forwards with 

 exaggerated action of the shoulder muscles, so as to compensate 

 for the defect in the extensors of the elbow. The lameness is 

 characterised by stumbling, particularly on uneven ground, and 

 later by a sliding motion of the foot when the limb is extended. 



Cases of radial paralysis due to fractured first rib can sometimes 

 be diagnosed by drawing the affected limb towards the opposite 

 side of the body, and sharply returning it to its former position. 

 By applying the ear over the scapula while this manipulation is 

 performed by an assistant crepitation may be detected. 



Not infrequently paralysis is partial. The greater number of 

 cases seen by Moller in the summer of 1887, and certain cases observed 

 later, were distinguished by the fact that the function of the caput 

 medium and of the extensors lying in the region of the fore-arm was 

 clearly retained, whilst the other portions of the caput muscle 

 appeared relaxed ; when weight was placed on the foot these contracted 

 in the usual way. For this reason the lameness has a peculiar 

 character : during the period when weight is placed on it, and at 

 the moment when the limb is perpendicular, the shoulder is suddenly 

 jerked forwards, causing the disease to present a certain similarity 

 to suprascapular lameness. But as these involuntary movements 

 take place in a forward direction (best seen by moving the horse 

 slowly and viewing it from the side), the disease is readily distinguished 

 from the above lameness, where the shoulder moves directly 

 outwards. 



The reason of the caput medium being sometimes unaffected in 

 (his lameness must be sought in the distribution of the nerves. 

 From the point of origin twigs are first given off to the head of the 

 caput magnum muscle ; these are comparatively short fibres, whilst 

 the main stem distributed to the caput medium and parvum and 

 extensors of the foot lying in the fore-arm region is much longer, 

 and is, therefore, not involved to the same extent in any strain 

 occurring here. The correctness of this view is supported both by 

 the fact that partial paralysis occurs accidentally after mechanical 

 injuries, and that in such cases function is always retained in the 

 extensors of the knee, of the fetlock, and of the foot. 



As already stated, paralysis in these groups of muscles can be 

 detected during movement both by sight and feeling. Muscular 

 atrophy occurs sooner or later, and to an extent varying according 

 to the amount of functional disturbance. Sometimes, though no 



