**Core Concept**
The talus bone in the foot is supported by a ligamentous structure that plays a crucial role in maintaining the integrity of the ankle joint. This ligament acts as a stabilizer and helps to prevent excessive movement of the talus within the ankle mortise.

**Why the Correct Answer is Right**
The correct ligament supporting the head of talus is the **Deltoid ligament**. The deltoid ligament is a strong, fan-shaped ligament that provides medial (inner) support to the ankle joint. It originates from the medial malleolus of the tibia and inserts into the medial surface of the talus, calcaneus, and navicular bones. The deltoid ligament helps to resist eversion (outward rotation) of the ankle and prevents excessive movement of the talus.

**Why Each Wrong Option is Incorrect**
**Option A:** The **Anterior talofibular ligament** is actually a ligament that supports the anterior (front) aspect of the ankle joint, but it does not provide significant support to the head of the talus.

**Option B:** The **Posterior talofibular ligament** is another ligament that supports the posterior (back) aspect of the ankle joint, but like the anterior talofibular ligament, it does not provide significant support to the head of the talus.

**Option C:** The **Calcaneofibular ligament** is a ligament that supports the lateral (outer) aspect of the ankle joint, and it does not provide significant support to the head of the talus.

**Clinical Pearl / High-Yield Fact**
The deltoid ligament is often injured in ankle sprains, particularly those that occur due to eversion (outward rotation) of the ankle. A thorough understanding of the ligamentous anatomy of the ankle is essential for accurate diagnosis and management of ankle injuries.

**Correct Answer:** D. Deltoid ligament