Additionally, there's an external sphincter, at the level of the urogenital diaphragm in the floor of the pelvis which is under voluntary control.
此外,也存在尿道外括约肌,位于盆底的尿生殖膈,受意识支配。
英语百科
Urogenital diaphragm
Older texts have asserted the existence of an urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of the urogenital diaphragm (perineal membrane) and superior fascia of the urogenital diaphragm.