Okay, the user provided a question about which carpal bone is prone to avascular necrosis, but the options are missing. Hmm, that's a bit tricky. Let me recall the carpal bones. The carpal bones are arranged in two rows. The proximal row includes the scaphoid, lunate, triquetrum, and pisiform. The distal row has the trapezium, trapezoid, capitate, and hamate.

Avascular necrosis (AVN) occurs when blood supply to a bone is disrupted. Which of these carpal bones is most affected? I remember that the scaphoid is the one most commonly involved. Why? Because the scaphoid's blood supply is primarily from the distal end, supplied by the radial artery. If there's a fracture, especially in the proximal third, the blood supply can be compromised, leading to AVN in that part.

Wait, the lunate can also be affected, but in a different context. Kienböck's disease is avascular necrosis of the lunate, often due to repetitive trauma or vascular issues. But the question might be more about the scaphoid. Let me check: scaphoid fractures are common, and their blood supply is tenuous, especially in the proximal part. The lunate's AVN is less common but possible. So the answer is likely the scaphoid.

But the user's options are A-D with no labels. Maybe the correct answer is the scaphoid. Let me structure the explanation accordingly. The core concept is the blood supply of carpal bones. The scaphoid's blood supply is from the radial artery via the dorsal and palmar branches, entering distally. If there's a fracture, especially in the proximal third, the blood can't reach that area, leading to AVN. The lunate's AVN is a separate entity. The other bones like capitate or trapezoid have more robust blood supplies. So the correct answer is scaphoid. The clinical pearl would be that scaphoid fractures have a high risk of AVN due to their terminal vascular supply.

**Core Concept**
Avascular necrosis (AVN) in carpal bones occurs due to disruption of their blood supply. The **scaphoid** is most vulnerable because its vascular supply is terminal and enters distally, making proximal fractures prone to ischemia.

**Why the Correct Answer is Right**
The **scaphoid** receives blood primarily via the radial artery branches, which supply the distal third. Fractures in the proximal third can occlude this vascular supply, leading to AVN. Its "watershed" region at the midshaft further increases risk. Clinically, delayed healing or nonunion is common in scaphoid fractures due to this poor vascularity.

**Why Each Wrong Option is Incorrect**
**Option A:** *Lunate* can undergo AVN (Kienböck’s disease), but this is less common and typically due to chronic microtrauma, not acute fractures.
**Option B:** *Capitate* has a robust blood supply from the median and radial arteries, making AVN rare.
**Option C:** *Trapezium* is supplied by the superficial palmar arch and is less prone to AVN compared to the scaphoid.

**Clinical

✓ Correct Answer: B. Scaphoid