Fractured Sacrum, Posterior View

Description

Posterior sacral anatomy is presented with the median sacral crest running in the midline and the paired intermediate and lateral sacral crests flanking it over the fused posterior elements of S1 to S5. Inferiorly, the sacral canal opens at the sacral hiatus between the sacral cornua, just superior to the coccyx at the sacrococcygeal junction. A clearly marked fracture line tracks along the midline near the hiatus, separating the posterior arch and interrupting the normal continuity of the dorsal surface and its relationship to the posterior sacral foramina laterally. Midline sacral fractures matter because they sit immediately posterior to the sacral canal and sacral nerve roots, so displacement can translate into neurologic findings that range from saddle anesthesia to bowel or bladder dysfunction. Trauma patterns that split the sacrum, including transverse or U-shaped configurations, are often discussed in the context of spinopelvic dissociation, and posterior surface disruption near S4 to S5 raises practical concerns for caudal epidural access when landmarks are distorted by injury. Expect instability. This posterior perspective also helps correlate external bony landmarks with CT and fluoroscopic findings when the fracture involves the dorsal cortex and posterior elements rather than the sacral ala. Use this figure in orthopedic trauma and spine surgery teaching to explain sacral fracture morphology, surface landmarks (sacral hiatus, cornua, crests), and why posterior injuries can threaten sacral nerve function. It also fits well in radiology and emergency medicine materials that pair posterior anatomy with axial and sagittal CT reconstructions for classification and operative planning. Anatomical accuracy verified by SciePro's Medical Advisory Board.