The sacrum is a triangular bone at the base of the spine that sits between the two iliac bones of the pelvis. It plays a central role in transmitting force between the spine and the lower extremities, and its position directly affects the alignment of the pelvic bowl. During pregnancy, the combination of increasing body weight, relaxin-driven ligament laxity, and the postural changes that accompany a growing uterus make sacral misalignment more likely to develop. Uneven loading patterns — favoring one leg, sitting asymmetrically, or compensating for hip or back pain — can accelerate this process. The result is a sacrum that has shifted out of its optimal position relative to the iliac bones, creating asymmetry in both the pelvic joints and the soft tissues attached to the uterus.
The clinical significance of sacral misalignment during pregnancy extends beyond the discomfort it may produce. When the sacrum is positioned asymmetrically, the tension in the round ligaments and uterosacral ligaments can become uneven, which may affect the shape and symmetry of the uterine space the baby occupies. This is the structural relationship that the Webster Technique is designed to evaluate and address. Dr. Bronstein at Beacon Clinic of Chiropractic assesses sacral position as part of every Webster Technique evaluation for Arroyo Grande and Grover Beach prenatal patients in California, using palpation and postural observation rather than imaging to characterize the misalignment pattern present.
