Also note the urethra on the sagittal image, which is composed of four parts: the preprostatic (1), prostatic (2), membranous (3), and spongy or penile (4) urethra. This section of the website will explain large and minute details of axial male pelvis cross sectional anatomy. The display of normal anatomy is enhanced by the ability of the MRI device to provide images in direct transverse, sagittal, and coronal planes. (c) Sagittal T2-weighted MR image shows the expected increase in the anorectal angle to 97° during straining and defecation. The artificial urinary sphincter consists of a pressurized reservoir (arrow in a) in the abdomen, a sphincter cuff that goes around the bulbous urethra (arrowhead in b), and a pump placed in the scrotum (*). Transperineal, transrectal, transvaginal, and, on rare occasions, transurethral US is used in evaluation of pelvic floor dysfunction. Urethral sling in a 70-year-old man.