This is a vintage radiographic image of an adult pelvis, labeled with anatomical features. The image is a black and white X-ray, showing the bony structures of the pelvis in varying shades of gray. Several labels with lines point to specific bones and features. The image is titled 'FIG. 143. Radiograph of the Pelvis of an adult.' and is part of 'PLATE XXIII'. Key features labeled include: * **Sacroiliac joint:** The connection between the sacrum and ilium. * **Head of femur:** The rounded top of the thigh bone. * **Greater trochanter:** A bony prominence on the femur. * **Floor of acetabulum:** The socket in the pelvis that receives the head of the femur. * **Lesser trochanter:** A smaller prominence on the femur. * **Spine of ischium:** A bony projection on the ischium. * **Tuberosity of ischium:** A rough area on the ischium. * **Body of pubis:** The main part of the pubis bone. * **Apex of coccyx:** The tip of the tailbone. * **Transverse process of 5th lumbar vertebra:** A projection from the lumbar vertebra. * **Spine of 5th lumbar vertebra:** A bony projection from the lumbar vertebra. * **Ilium:** The large, flared bone of the pelvis. * **Spine of second sacral vertebra:** A bony projection from the sacrum. The image is a medical illustration, likely from an anatomy or radiology textbook. It appears to be aged, with some discoloration and wear.