PARALYSIS OF SUPRASCAPULAR NERVE. 
511 
manger or other firm objects, or against another horse, as in cavalry 
attacks. It is therefore common in cavalry horses, in runaways, or in 
animals which have been struck by the pole of a carriage. Cadiot has 
seen it follow casting for operation ; the horse had been kept down for 
a long time. At the end of two months wasting of the postea-spinatus 
was very marked. Reported cases seem to indicate that it sometimes 
accompanies hemoglobinuria and rheumatism. Hansen saw a case 
produced by a door slamming and striking the animal. The causes are 
therefore similar to those of bursitis intertubercularis. The difference 
consists in this, that violence to the unloaded limb thrusts it back, and 
is apt to cause this paralysis, whereas violence to the limb when support¬ 
ing the body causes contusion of the shoulder, backward movement 
being then impossible. This paralysis is therefore more likely to be 
produced when the shoulder is struck by a heavy, slow-moving body than 
where the blow is given suddenly ; in the latter case the biceps and its 
bursa are endangered. 
The symptoms are explained by the loss of function in the muscles 
which act as lateral ligaments to the shoulder-joint. Whilst nothing 
abnormal can be remarked as long as the limb is rested, sudden abduc¬ 
tion occurs immediately weight is placed on it, and at the moment when 
the foot is perpendicularly below the body. The scapula and humerus 
aie then jerked away from the wall of the thorax. This movement is 
best seen when the horse is slowly walked in a straight line. 
I he disease then is distinguished by lameness when weight is placed 
on the limb (suppoiting leg lameness), by abduction of the limb, and by 
jerking of the shouldei outwards at the moment when the leg is perpen- 
diculai. Atiophy of the paralysed muscles occurs later, and is most 
marked in the supraspinatus, infraspinatus, and two teres muscles, 
whilst the deltoid, which receives its innervation from the circumflex 
nerve, remains intact. The atrophy is rendered more noticeable by the 
increased projection of the spine of the scapula. 
Roloff saw a horse which had suddenly exhibited double-sided shoulder 
lameness during heavy work, and found marked atrophy of the supra- and 
infra- spinatus muscles. The shoulder-joint was thrust outwards. In this 
case piobably theie was double-sided paralysis of the suprascapular nerve. 
In cattle, on the other hand, a somewhat similar condition is caused by over- 
extension or relaxation of the adductor groups (MM. subscapularis and teres 
major). It is seen in particular races, such as the Holsteiners, particularly in 
winter ; in summer, when the animals are pastured, it often disappears. 
Prognosis and. course. Paralysis caused by mechanical influences 
is known to be less favourable than the rheumatic forms, and treatment 
is often unsuccessful. As a general rule, prognosis is much less favour¬ 
able than in paralysis of the radial nerve, though recovery sometimes 
occurs in six to eight weeks. Otherwise, and especially if the lameness 
