ABNOEMALITIES IN THE PARTURIENT PASSAGES 173 



by the owner than given a chance for an eventual recovery after 

 such a fracture. 



The treatment depends on the degree of constriction. 

 When the pelvic dimensions are but little reduced, total extrac- 

 tion may be possible, while a foetus relatively too large makes 

 such a procedure impracticable. For further information, I 

 refer to the chapter on excessive development of the foetus. 



MORBID ALTERATIONS IN THE CERVIX UTERI. 



The cervix uteri forms the connecting link between the 

 vagina and uterus. Before dilatation it is firmly closed, the 

 transverse folds of the utero-vaginal mucous membrane, palma 

 plicata, lie so closely together that the finger cannot pass into 

 the cervical canal. During natural parturition the cervix uteri 

 dilates to such an extent that uterus and vagina form a con- 

 tinous canal. 



Pathological states met with iu practice preventing com- 

 plete dilatation of the cervix are: Spasm of the circular mus- 

 cular layer, total or partial obliteration and tumors. 



Spasm of the circular muscular layer is less frequent in 

 practice than is ordinarily stated. The question has been 

 raised whether it is possible that a tonic spasm could create a 

 closure sufficient to resist the boring movements of the finger 

 or hand. We must admit that muscular contraction in itself 

 does not suffice, but may do so when assisted by other 

 facto:s. 



The cervix uteri is composed of a plicated mucosa, neces- 

 sary for an eventual dilatation ; further, a submucosa and a 

 serosa. The mnscularis consists of a strong inner layer, the 

 fibres of which are circular and extend to the beginning of the 

 vagina ; further, an external horizontal layer, ending in the 

 vagina. Between these layers numerous blood vessels and 

 nerves are found. 



The cervix uteri of the cow is physiologically rigid. As a 

 result of the infiltration taking place with the first pains,, this 

 rigidity diminishes and may be overcome by mechanical pres- 

 sure from the uterus. 



