Avascular necrosis can be a possible sequelae of fracture of all of the following bones, except:
**Core Concept**
Avascular necrosis (AVN) is a condition characterized by the death of bone tissue due to a lack of blood supply. It can occur as a complication of various injuries, including fractures, which disrupt the blood flow to the affected bone.
**Why the Correct Answer is Right**
Avascular necrosis is a well-documented complication of fractures, particularly in weight-bearing bones. The femoral head is a classic example, where a fracture can lead to AVN due to the femoral head's limited blood supply. The humerus, scapula, and pelvis are also susceptible to AVN after fractures. In contrast, the bones of the upper limb are less likely to develop AVN due to fractures, as they have a more robust blood supply.
**Why Each Wrong Option is Incorrect**
**Option A:** The femur is a weight-bearing bone that is prone to AVN after fractures, making it an incorrect choice.
**Option B:** The scapula can develop AVN after fractures, especially those involving the neck or glenoid, making it an incorrect choice.
**Option C:** The pelvis can also develop AVN after fractures, particularly those involving the acetabulum or femoral head, making it an incorrect choice.
**Option D:** The radius and ulna are bones of the forearm, which are less likely to develop AVN after fractures due to their robust blood supply.
**Clinical Pearl / High-Yield Fact**
Avascular necrosis is more common in weight-bearing bones, particularly those with limited blood supply, such as the femoral head and pelvis.
**Correct Answer:** D. The radius and ulna are bones of the forearm, which are less likely to develop AVN after fractures due to their robust blood supply.