RUPTURES, 263 
e 
common in cattle or dogs, but are seen in swine (Ostertag) and birds 
(Larcher) frequently. Complete rupture of muscles is much less com- 
mon than that of tendons or of bones ; when it occurs, it is either the fleshy 
part which is affected or, as is more commonly the case, the musculo-tendin- 
ous portion. J/ncomplefe ruptures involving only a few fibres are facts of 
daily occurrence: the partial ruptures of the /o-spina/is muscle in horses 
secured in a recumbent position are frequently observed. (See AZyositis.) 
Lesions of degeneration of muscular fibres promote ruptures. In man, 
these degenerations have been observed in typhoid fever, smallpox and 
other infectious diseases; they are also observed in animals during an- 
alogous affections. Rupture may sometimes occur in muscles absolutely 
sound, under the influence of a violent contraction. Muscles in condition 
of activity have an enormous resisting power. Experiments have shown 
that in dogs the biceps is ten times more resisting during life than after 
death ; from this some have concluded that rupture was impossible during 
the state of contraction for them. Antagonistics are those which would 
bring on distension and rupture of the relaxed muscle ; but inco-ordinated 
contraction may overcome the resistance of the muscular fibre, and it is 
thus that the great majority of ruptures take place. 
In colts and in calves, sometimes, during the few hours following birth, 
one observes pseudo-paralysis of one or several members, due to muscular 
ruptures. On a two-day-old colt which was unable to stand up, and was 
killed, Knoll found the anterior extensor of the phalanges ruptured on 
the right anterior leg. Sussdorf has reported a similarcase. Whether the 
accident is the result of powerful contraction of the muscles, as Sussdorf 
believes, or of dystokial difficulty, it is always serious, and treatment ought 
not to be undertaken except on animals of great value. 
In adults, muscular ruptures are observed especially after violent efforts, 
‘falls, slips or blows. Partial ruptures involve the superficial or the deep 
part of the organ; long muscles are more exposed than the others ; thin, 
flat muscles, those that are not surrounded by a restraining aponeurosis, 
rupture most commonly in their superficial layers; the muscles that have 
a thick sheath rupture rather towards the center (Rigot). As the fibres do 
not give way on the same level, the surface of the fracture is always ir- 
regularand ragged. An exudation of blood fills the space left between the 
divided ends. 
Ruptures of the following muscles have been recorded: /ecvoral, mas- 
toido-humeralis, subscapularis, coraco-radialis, extensors of the fore-arm, 
ilio-spinalis, anterior crural muscles, bifemoro-calcaneal, Ubto-premetatar- 
sal, and diaphragm. The observations 2, 3 and 4 of the report of Rigot 
relate to the rupture of the subscapularis muscle. Tearings of the 
coraco-radialis are at times partial and again complete. Goubaux has 
