The Pelvis and Lower Limbs

Abstract

The pelvis is ring shaped and is made up of the iliac bones, with their apophyses, the ischium with its apophyses, the pubic bones with the synchondrosis inserted, the sacrum, and the sacroiliac articulations, of which two-thirds are an amphiarthrosis since an articular fibrocartilaginous disc is inserted between the two joint surfaces, and one-third a synovial articulation. The stability of the pelvic ring is maintained by the iliolumbar, sacroiliac, sacrotuberous, and sacropinous ligaments. The pelvis is highly vascularized: the hematic contribution is mainly provided by the hypogastric vessels, or internal iliac vessels, which start close to the pelvic arch; other important vessels include the upper gluteal arteries, often damaged in posterior fractures, and the internal obturator and pudendal vessels, often damaged in fractures of the pubic branches. Innervation is provided by the nerves from the lumbar and sacral plexus, which pass through the posterior part of the pelvic ring. The site of the fracture is generally predictive of the type of vascular, neurological, and visceral lesions that may be associated.