940 PARALYSIS OF THE HIND LIMB. 



extended, and the fetlock and front of the pastern resting on the 

 ground. In advancing, the limb appears to dwell, becoming rigidly 

 extended backwards, and then dragged forwards, renewing contact 

 with the ground by the flexed fetlock or the plantar surface of the 

 foot. In backing, at first the fetlock is straightened and the heels 

 come to the ground, then the foot is drawn stiffly backwards, the 

 fetlock is suddenly shot forwards and the heels are raised from the 

 ground. At liberty in a field, the patient can canter, trailing the 

 defective limb, which touches the ground by the front of the fetlock 

 and toe-wall of the foot. 



Goubaux gave an excellent description of paralysis of the external 

 popliteal nerve as early as 1848. His case was caused by a violent 

 contusion, and was unsuccessfully treated by repeated blistering 

 along the course of the nerve. 



Szidon states having seen paralysis of the external popliteal nerve 

 consequent on injury by small shot. 



An interesting case of this kind has been recorded by Moller. An 

 eight-year-old Belgian gelding was one morning found lame hi his 

 stall without visible cause. Seen next day, he exhibited marked 

 uncertainty in moving his hind limbs, suggesting partial paralysis, 

 but it soon became evident that only the right hind limb was affected. 

 Whilst the left hind limb was moved and weight was placed on it in 

 the usual way, the right leg was carried close to the middle line of the 

 body (adducted) and was placed too far in advance and too near the 

 right side, causing the animal to fall towards the right side ; the body 

 was only saved from coming to the ground by a rapid spring with 

 the left foot. At the same time the stifle and hock joints were 

 excessively extended, and the phalanges flexed (plantar flexion). The 

 gait was clumsy and insecure in the highest degree. These move- 

 ments recurred at every step ; the animal was incapable of trotting. 

 The uncertainty of walking was aggravated by the abnormal flexion 

 of the phalanges, which at times caused the animal to walk on the 

 front of the fetlock -joint itself. 



By passing a rope round the right fetlock, and so drawing the limb 

 outwards and extending the fetlock each time the animal attempted 

 to move, walking became perfectly easy. Immediately such assistance 

 was withdrawn, however, the previous difficulties returned. At first 

 no anatomical change in the limb could be noted, nor was there any 

 sign of local pain or inflammation, but by placing the hand on the 

 limb during movement, the muscles in front of the tibia, as well as 

 the semi-tendinosus, semi-membranosus, and biceps femoris were 

 found to remain relaxed and without movement. Sensation in the 



