Structures at risk from medially placed acetabular screws.

The anatomical structures adjacent to fourteen acetabula were studied to identify structures that are at risk from acetabular screws. There were six embalmed acetabula, four acetabula from two fresh autopsy specimens, and four acetabula that were studied during two gynecological operations. Models were constructed to show where these screws can penetrate. Medially placed screws either penetrated or came dangerously close to the external iliac vein; the obturator artery, nerve, and vein; and tributaries of the internal iliac vein. To avoid injury to the medial vascular structures, screws should not be placed in the anterosuperior quadrant of the acetabulum.