Type IV cervical atresia. (A) Cervical canal tissue. Red and blue arrows indicate cervical canal glands. The black arrow indicates a nerve fiber (HE?×?100). (B) The red arrow indicates regularly arranged well-developed smooth muscle tissue (HE?×?100). (C) Histologicol intemal os of the uterus. The yellow arrow indicates endometrial tissue. The red arrow indicates cervical canal tissue (HE?×?40). (D) The red arrow indicates endometrial glands (HE?×?400).