ABSTRACT
Objective To investigate the distribution characteristics of motor endplates in musculuslevatorani of dif-ferent gestational ages. Methods 20~24 weeks female fetuses were categorized as Group A, and 24~28 weeks female fetuses as group B. Karnovsky-Roots iron cyanide copper staining ( hematoxylin) was used to study the aver-age weight, the morphology, distribution and changes in number of motor end plate. Results The motor endplates morphology and distribution of consistent oval of 20 ~28 weeks female fetuses showed a curve distribution in the musculuslevatorani fibers foreign 1/3 . The weight and numbers of motor endplates in Group A were less than those of group B. Conclusion 20 ~28 weeks female fetuses' musculuslevatorani are visible on the motor end plates, and no significant difference is found in morphology and distribution of the curve along the muscle fibers. The num-ber of motor endplates increases with the increase of anal muscle weight mentioned.