A 23 year old construction worker presents to the emergency room after falling down on his outstretched right hand. X-ray reveals a fracture of one of the wrist bones. The ER physician is concerned about the risk for avascular necrosis. Which of the following bones was fractured?

**Core Concept**
The question is testing the student's knowledge of the blood supply to the wrist bones, specifically the risk of avascular necrosis associated with fractures of certain bones.

**Why the Correct Answer is Right**
Avascular necrosis of the scaphoid bone is a well-known complication of scaphoid fractures. This is because the scaphoid bone receives its blood supply primarily from the dorsal (back) aspect, which is often disrupted in fractures. The scaphoid bone is the most common site for avascular necrosis in the wrist due to its unique blood supply.

**Why Each Wrong Option is Incorrect**
**Option A:** The lunate bone is another carpal bone in the wrist, but it is not typically associated with avascular necrosis after a fracture.
**Option B:** The triquetrum bone is a carpal bone in the wrist, but it is not commonly associated with avascular necrosis after a fracture.
**Option C:** The pisiform bone is a small carpal bone in the wrist that is not typically associated with avascular necrosis after a fracture.

**Clinical Pearl / High-Yield Fact**
The scaphoid bone is the most common site for avascular necrosis in the wrist, and early recognition and treatment of scaphoid fractures are crucial to prevent this complication.

**Correct Answer:** C. The scaphoid bone is the most susceptible to avascular necrosis after a fracture.

✓ Correct Answer: D. Scaphoid