The posterior portion of the prostate gland is covered by which membranous tissue layer?

Denonvillier's Fascia is the correct choice as it serves as the membranous tissue layer that covers the posterior portion of the prostate gland. This fascia is a connective tissue structure that separates the prostate gland from the rectum, providing a barrier that is essential for maintaining the anatomy of the pelvic region.

Understanding Denonvillier's Fascia is crucial in urological anatomy and procedures, as surgical interventions involving the prostate need to take this fascia into account to prevent damage to surrounding structures, such as the rectum. The integrity of this fascia is also important for the proper functioning of the prostate and its surrounding organs.

Other choices, such as the peritoneum, the pouch of Douglas, and visceral fascia, are related to other anatomical features or functions in the pelvis but do not specifically cover the posterior aspect of the prostate gland. The peritoneum is the serous membrane lining the abdominal cavity, while the pouch of Douglas refers to the space formed by the peritoneum that extends between the uterus and rectum in females. Visceral fascia is a more general term that can refer to connective tissue surrounding organs but does not specifically pertain to the prostate.