Anatomy of pelvic trauma: structure and function of ligaments around sacroiliac and pubic symphysis, and bone mineral density of pelvic bones

Abstract

This review is based on the literature published between 2000 and 2023 and presents an up-to-date evidence-based discussion of anatomical considerations relevant to the management of pelvic trauma. In addition, it discusses the significance of the pelvic ligaments in stabilizing the pelvic ring and of bone mineral density (BMD) in fragility fracture of the pelvis (FFP), which is becoming increasingly common in today’s aging societies. Following an overview of the anatomy and function of the sacroiliac joint (SIJ), the pubic symphysis, and the surrounding ligaments, the suitability of the widely-used Young-Burgess classification (YB) of high-energy impact pelvic ring fractures, which emphasizes the role of the ligaments in pelvic ring injuries, is discussed. Based on the current body of knowledge, using 2.5 cm of pubic symphysis diastasis as the determinant for surgical intervention in anterior-posterior compression fracture is questioned, and evaluation under anesthesia and lateral stress radiography for accurate diagnosis and treatment planning is proposed instead. The review underscores the need for further research on how the pelvic ligaments can provide optimal stability in the treatment of various types of pelvic fracture. On the other hand, for fragility fracture of pelvis (FFP) in older adults caused by low-energy trauma, the emphasis is on the fragility of the bones. To better manage FFP, the importance of understanding the distribution of BMD in the pelvis is highlighted. Dual-energy X-ray absorptiometry is a common method for measuring BMD, but it has drawbacks. The advantages of measuring BMD using Hounsfield units on computed tomography scans as an alternative method are discussed. An understanding of these issues may lead to better management of the increasing number of FFP cases in older people with reduced BMD.

Keywords

• sacroiliac joint
• pubic symphysis
• pelvic fracture
• ligament
• bone mineral density