The pouch of Douglas, also known as the recto-uterine pouch, is a small, triangular-shaped space located between the uterus and the rectum in the female reproductive system. It is named after James Douglas, a Scottish anatomist who first described it in the 18th century.

Anatomy:
The pouch of Douglas is bordered by the posterior wall of the uterus and the anterior wall of the rectum. It is lined with a thin layer of peritoneum, the same tissue that covers the abdominal organs. The pouch of Douglas is located in the pelvic cavity, which is the space within the bony pelvis that contains the reproductive and urinary organs.

Physiology:
The pouch of Douglas is an important anatomical landmark that is commonly used in gynecological examinations and procedures. It can be accessed by inserting a finger or instrument into the vagina and pushing upwards towards the cervix. The pouch of Douglas is an important site for the diagnosis and treatment of conditions such as endometriosis, ovarian cysts, and pelvic inflammatory disease.

Overall, the pouch of Douglas is an important anatomical structure in the female reproductive system that plays a key role in gynecological examinations and procedures.