CCMaher&S.Francis White Line Pelvic Floor Muscles Anus Coccygeal Raphe he pelvic floor muscles form a sling around the lower pelvic outlet and when contracted offers support to the lower bowel, the genital tract and the lower urinary tract These muscles arise from the white line on lateral pelvic side-wall and interdigitate with each other and the anococcygeal raphe in the centreThe pelvic floor muscles form a sling around the lower pelvic outlet and when contracted offers support to the lower bowel, the genital tract and the lower urinary tract. These muscles arise from the white line on lateral pelvic side-wall and interdigitate with each other and the anococcygeal raphe in the centre