Symphysis pubis distance in adults: a retrospective computed tomography study

In this retrospective study, symphysis pubis (SP) distance was measured by transverse computed tomography scans. The relation between the SP distance and age, gender, number of birth and body-mass index was studied.

Symphysis pubis joint distances were evaluated for the patients who had undergone abdominal or pelvic computed tomography examination for other medical reasons between the dates of March and May 2007. Anterior, middle, and posterior SP joint distances were measured at transverse planes. Normal joint width in women and men was determined. The relation between obtained values, and age, gender, number of birth, as well as body-mass index was studied.

Symphysis pubis narrows at anterior concurrently with ageing (r = -0.150; P < 0.001) [corrected] Narrowing, though less, is also observed at posterior (r = -1.50 P = 0.000); however, middle part does not change (r = 0.030; P = 0.489). Number of birth and body-mass index values do not affect SP width. The widths measured at anterior and middle of the SP were significantly higher in women (P = 0.010 and P = 0.002).

Osteoarthritic changes develop in SP with ageing. However, osteoarthritis in SP, was found to be clinically and radiologically different from that in other symphyseal joints, as SP hardly ever moves, and vertically processing interpubic disc combines pelvis girdle with counterforces, and is supported by very strong ligaments and muscles. Anterior and middle part of the SP joint is wider in women, because fibrocartilaginous disc is too thick to provide the mobility.