NORMAL PELVIC ANATOMY

AP VIEW OF NORMAL PELVIS



AP VIEW OF PELVIS SHOWING IMPORTANT ANATOMICAL LINES

• The five bones that comprise the pelvis are the ilium, ischium, pubis, sacrum, and coccyx.
• Most trauma to the pelvis and hips can be evaluated with an AP projection of the pelvis and hips. Other injuries require special projections such as anterior and posterior obliques views of the pelvis, frog-lateral view of the hip and groin-lateral view.
• CT of the pelvis is the technique of choice for evaluating complex fracture patterns, degree of displacement and soft tissue injury.
• Symptoms from fractures of the hip, acetabulum and pelvis may be quite similar, thus, a full AP pelvis radiograph including the hip must be obtained if any of the above fractures are expected.
• The femurs should be internally rotated when obtaining an AP pelvis film so that the femoral necks can be appropriately assessed for fractures.

GENERAL CONSIDERATION FOR PELVIS AND HIP

• The pelvis and hips constitute one of the most diagnostically challenging areas of the body for two main reasons. First, it is the single area of the body where obtaining a lateral projection provides little additional information. Second, soft tissue injuries are difficult to assess with radiographs of the pelvis, but have greater clinical significance than in other areas of the body.
• Severe pelvic trauma is associated with hemorrhage in approximately 60% of cases. Hemorrhage is a principle factor leading to death in this patient population.
• Systematically examine all bony structures of the pelvis and femurs for symmetry, cortical breaks and joint spaces (sacroiliac, hip and symphysis pubis joints). Also carefully examine the common injury regions such as the femoral neck, iliac spine, acetabulum, inferior ramus of the ischium and superior pubic ramus.
• Avulsion injuries are common and can be easily missed. Examine the frequent sites of avulsion, which are the anterior superior iliac spine, anterior inferior iliac spine and ischial tuberosity.
• Remember that the pelvis is a ring and it is commonly broken in two or more places. The pelvic ring must remain intact for the fracture(s) to be considered stable. If the ring is compromised, it is an unstable pelvic fracture.
• Significant pelvic ring disruption (PRD) leads to rupture of the bladder or urethral injury in approximately 20% of cases. Evaluation of the urethra with retrograde uretrogram should be performed in all male patients with PRD prior to Foley catheter placement.