The superficial transverse perineal muscle acts to support the

The superficial transverse perineal muscle arises from the ischial ramus and is inserted into the perineal body. All three superficial muscles are supplied by the pudendal nerve. In the female, the bulbospongiosus is separated from the contralateral muscle by the vagina

Explanation:

between the two muscle layers is the myenteric or auerbach's plexus, which controls peristalsis. in the colon, the muscularis externa is much thicker because the feces are large and heavy, requiring more force to push along. the stomach has a third layer of muscularis externa: the inner oblique layer.