**Core Concept**
The anatomical snuffbox is a critical area of clinical examination, particularly in the context of wrist injuries. It is bounded by the tendons of the extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus muscles. Injuries to the scaphoid bone, one of the eight carpal bones in the wrist, can often present with pain in the anatomical snuffbox.

**Why the Correct Answer is Right**
The patient's history of a fall on an outstretched hand and pain in the anatomical snuffbox are highly suggestive of a scaphoid fracture. The scaphoid bone is a common site of fracture, particularly in young adults, due to its location and the mechanism of injury. The bone is prone to fracture when the wrist is subjected to a fall on an outstretched hand, causing compression and stress on the scaphoid bone. This mechanism of injury is consistent with the patient's reported fall.

**Option A:** Colles' fracture typically presents with a visible deformity known as a "dinner fork" deformity, which is not consistent with the patient's clinical presentation.

**Option B:** Lunate dislocation is a type of wrist injury that involves the dislocation of the lunate bone. While it can cause wrist pain, it is less likely to present with pain in the anatomical snuffbox.

**Option C:** Barton's fracture is a type of fracture that involves the distal radius. It typically presents with a visible deformity and is not consistent with the patient's clinical presentation.

**Clinical Pearl / High-Yield Fact**
The scaphoid bone is the most commonly fractured carpal bone, accounting for approximately 80% of all carpal fractures. It is essential for clinicians to be aware of the typical presentation of scaphoid fractures, including pain in the anatomical snuffbox, to ensure prompt and accurate diagnosis.

**Correct Answer:**
✓ Correct Answer: D. Scaphoid fracture