Case Study Osteoporosis
1. What is meant by a "complete, comminuted, intertrochanteric fracture of the right hip"?
A. Complete - refers to a fracture completely through the bone:
B. Comminuted - refers to a fracture in which the broken bone has shattered into several smaller pieces:
C. Intertrochanteric - refers to a fracture located between the greater trochanter and lesser trochanter of the femur:
2. Draw a picture of what you think Margaret's fracture looks like.
3. The radiologist reported signs of osteoporosis. Describe the characteristics of an osteoporotic femur as seen on an X-ray. (How does it differ in appearance from a normal femur?)
Osteoporosis is marked by a decreased bone volume. Loss of spongy ("cancellous") bone is greater than loss of compact bone. In the femur, osteoporotic changes would include a thinning of the outer layer of compact bone around the epiphyses and thinning of the bony collar around the diaphysis. There would also be loss of cancellous bone in the proximal and distal epiphyses. These changes weaken Margaret's femurs and make them more vulnerable to fracture.
In osteoporosis, the normal balance between the activity of bone-building osteoblasts and bone-resorbing osteoclasts is upset in favor of the osteoclasts. Thus, over time, there is loss of total bone volume. While everyone experiences slow, gradual loss in bone volume after age 30, those with osteoporosis have accelerated loss.
4. Describe the microscopic features of osseous tissue that normally help long bones withstand lateral stress without breaking.
A lateral stress placed on a bone (e.g. on Margaret's right femur) actually causes (A) compression of the bone on the side of impact and (B) stretching (tearing) on the side opposite of the impact.
Mid-way through the bone, these "compressive" and "tearing" forces cancel each other out, and thus tough, compact bone is not needed in the middle. Instead, this middle area (or "medullary cavity") is filled with yellow and red bone