CHAPTER 31

Anatomy of Retropubic Space

The boundaries of the retropubic space (space of Retzius) are the symphysis pubis anteriorly, the pubic rami laterally, and the sidewalls composed of pubic bone and obturator internus muscle. The anterior aspects of the proximal urethra and extraperitoneal portions of the bladder are seen upon exposure of the retropubic space. Figure 31–1 illustrates the view from above the retropubic space. Note that the floor of the retropubic space is formed by the fibrofatty outer lining of the vaginal wall termed endopelvic fascia, the perivesical fascia, and fibers from the levator ani muscle. This trapezoid structure provides support for the proximal urethra and bladder. Figure 31–2 shows a sagittal section of the normal anatomy of the pelvis. Figures 31–3, 31–4, and 31–5 demonstrate the relationship of the space to the urinary bladder, pelvic sidewall, upper thigh, and uterus.

The adipose tissue behind the symphysis between the bladder and the pubic bones can be gently separated by blunt finger dissection. The space is progressively developed from the superior to the inferior margin of the pubic symphysis (see Figs. 31–4, 31–5, and 31–6). The lateral development of the retropubic space extends to the perivesical space and terminates at the pelvic sidewall or, more precisely, at the obturator internus muscle (Fig. 31–7A–C and 31–8A, B). The lateral aspects of the retropubic space are demarcated in the dissections shown in Fig. 31–9A–F. The arcus tendineus originates from the obturator internus fascia. This whitish thickening of the obturator fascia can vary in its configuration from a single line to a wishbone or double-line structure. The pubococcygeus muscle (levator ani) in turn takes its origin from the arcus tendineus. The broad levator ani funnels downward into the depths of the pelvis. A portion of the levator ani arises from the inferior margin of the pubic ramus on either side in close proximity to the urethra, where it plays a key role in the sphincter mechanism to maintain urinary continence (see Fig. 31–8A, B). At the inferior extent of the space are located the urethrovesical junction, the anterolateral vaginal fornices, and the levator ani muscles (see Figs. 31–8A, B; 31–9A, and 31–10). The urethrovesical junction and the greater mass of the urinary bladder are exposed within the space of Retzius. Specifically, these structures lie on the floor of the retropubic space (Figs. 31–11A, B and 31–12). At the level of the proximal urethra, the pubourethral (puboprostatic) ligaments are noted; these are stylized in Figure 31–3. The actual structures run from the posterior symphysis pubis to the pubocervical fascia (endopelvic fascia) in contact with the proximal urethra on each side and are thought to be key structures for the maintenance of continence (Figs. 31–13A–D). The arcus tendineus fasciae pelvis, or white line, stretches from the posterior aspect of the symphysis pubis and continues in a downward sloping direction along the fascial margin of the obturator internus muscle to terminate at the ischial spine. The attachment of the pubocervical fascia (endopelvic fascia) to the white line partially maintains the support of the lateral vaginal wall. Detachments of the pubocervical fascia from the white line will lead to paravaginal defects. The arcus tendineus can be seen clearly (see Fig. 31–9A–F). It is a fascial landmark (see Figs. 31–11 and 31–12). From the point where the levator ani takes origin from the arcus, the muscle swings downward toward the midline, thus composing a portion of the pelvic floor (see Fig. 31–8B

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