**Core Concept**
The calcaneus is a tarsal bone in the foot that forms the heel and plays a crucial role in weight-bearing and shock absorption during gait. Its unique anatomy makes it prone to fractures, particularly avulsion fractures, which are common in sports and high-impact activities.

**Why the Correct Answer is Right**
The calcaneus is the most commonly injured tarsal bone due to its prominent position and role in weight-bearing. It is subjected to significant stress and impact forces during activities like jumping, running, and landing from a height. The calcaneus is also more susceptible to fractures due to its poor blood supply, which hampers healing. The bone's anatomy, with its medial and lateral tuberosities, also makes it vulnerable to avulsion fractures.

**Why Each Wrong Option is Incorrect**
**Option A:** The talus is a tarsal bone that is often injured in ankle fractures and dislocations, but it is not the most commonly injured tarsal bone. This is because the talus is protected by the malleoli and has a more stable position in the ankle joint.

**Option B:** The navicular bone is a tarsal bone that is often injured in sports, particularly in activities that involve quick changes of direction, such as soccer and basketball. However, it is not as commonly injured as the calcaneus.

**Option C:** The cuneiform bones are a group of three tarsal bones that form the medial arch of the foot. While they can be injured in certain conditions, such as rheumatoid arthritis, they are not the most commonly injured tarsal bones.

**Clinical Pearl / High-Yield Fact**
The Bohler's angle is a radiographic measurement used to assess the integrity of the calcaneus. A decreased Bohler's angle is indicative of a calcaneal fracture, particularly an intra-articular fracture. This is a high-yield fact that can be recalled during exams.

**✓ Correct Answer: D. Calcaneum**