Holographic analysis of the human pelvis.

Twelve fresh human pelves with preserved lumbar spines, hip joints, and ligaments, were tested by double-exposure and sandwich-hologram interferometry. During physiologic loadings (50-300 N), the pelvis moved as a whole downward and backward. Iliac wings exhibited marked undulation, except for the central part, which showed minor deformations. The sacrum moved downward and rotated forward over an axis 5-9 cm below the promontorium. Removal of the sacroiliac interosseous ligaments eliminated all joint movements and caused a tighter contact between articular surfaces. Removal of the sacrotuberous and sacrospinous ligaments had no influence on the pelvic behavior. The magnitudes of deformations as well as their underlying mineral contents were unequally distributed between the two pelvic sides. These results indicate that the sacroiliac interosseous ligaments are the main determinant of sacral movement. Asymmetric load transmittance to the hip joints might be responsible for the mineral content differences between the pelvic sides.