**Core Concept**
A stress fracture is a type of overuse injury characterized by a small crack in the bone, typically occurring in the weight-bearing bones of the lower limbs, such as the tibia, fibula, and metatarsals. It is caused by repetitive stress or overloading of the bone, leading to microfractures and subsequent bone remodeling.

**Why the Correct Answer is Right**
Stress fractures are typically associated with overuse injuries in athletes or individuals who engage in repetitive activities, such as running or jumping. The pathophysiology involves microfractures in the bone, which are caused by repeated stress and loading. The bone responds to this stress by laying down new bone tissue, leading to a strengthening of the affected area. However, if the stress continues, the bone may not be able to keep up with the demands, leading to a stress fracture.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because stress fractures can indeed occur in the metatarsals, which are a common site for stress fractures in runners and athletes.
**Option B:** This option is incorrect because stress fractures can occur in the tibia, which is also a weight-bearing bone and a common site for stress fractures.
**Option C:** This option is incorrect because stress fractures can occur in the calcaneus, which is also a weight-bearing bone and can be subject to overuse injuries.

**Clinical Pearl / High-Yield Fact**
Stress fractures often present with pain and swelling in the affected area, and a history of recent increased activity or overuse. They can be diagnosed with radiographs, bone scans, or MRI, and treatment typically involves rest, immobilization, and pain management.

**Correct Answer: D. Scaphoid bone.**