The urogenital triangle consists of three layers of fasciae that separate the superficial and deep perineal spaces (Figs. 1 and 2). They consist of the superficial fascia, which is attached laterally to the pubic arch and posterosuperiorly to the perineal membrane. As in the abdomen, there are two layers. There is a superficial fatty layer and a deeper membranous layer, referred to as the fascia of Colles instead of Scarpa. Anteriorly, the deep layer of the superficial fascia is continuous with Scarpa’s fascia in the abdomen. The fusion of this superficial perineal fascia and the perineal membrane forms the posterior boundary of the superficial perineal space. The middle fascial layer is the perineal membrane (inferior fascia of the urogenital diaphragm), which is also attached laterally to the pubic arch. In the middle of the line of fusion between the anus and the vagina is the central perineal tendon or perineum. The perineal membrane is fused posteriorly with the deeper superior fascia of the urogenital diaphragm to form the deep perineal space.
Figure 1. Female perineum, superficial dissection. Here the female perineum is partially dissected to show the inferior layer of the fescia of the rogenital diaphragm, otherwise known as the perineal membrane, and on the opposite side the course and distribution of pudendal vessels and nerves t the perineal region.
Figure 2. Female perineum, deeper dissection. Erectile bodies are present in the superficial pouch. The pudendal arteries and veins are shown, each on one side of the perineum. The glans and frenulum of the clitoris are also shown here. The striated ischiocavernosus muscle surrounds the proximal part of each corpora cavernosa, where they are attached firmly to the medial sides of the ischiopubic rami.