**Question:** Sudden dorsiflexion of foot may lead to which of the following injuries -

A. Ankle sprain
B. Fracture of the fifth cuneiform bone
C. Fracture of the calcaneus (heel bone)
D. Fracture of the talus bone

**Correct Answer:** D. Fracture of the talus bone

**Core Concept:** Sudden dorsiflexion of the foot can lead to ankle and tarsal bone injuries due to the forces applied to the foot and ankle complex during rapid dorsiflexion.

**Why the Correct Answer is Right:** In this scenario, dorsiflexion refers to the movement where the foot is elevated towards the shin, increasing the risk of injury to the ankle and tarsal bones. Among the given options, a fracture of the talus bone (D) is the correct answer. The talus bone is a small, triangular bone located between the tibia and fibula in the ankle joint. Sudden dorsiflexion can cause high-energy forces to be transmitted to the ankle, potentially leading to a fracture of the talus bone.

**Why Each Wrong Option is Incorrect:**

A. Ankle sprain (A) is a ligamentous injury, specifically affecting the ligaments around the ankle joint, not a fracture of a specific tarsal bone.
B. Fracture of the fifth cuneiform bone (B) is a tarsal bone injury, but it is not the most likely injury when dorsiflexing the foot suddenly, as the talus is more vulnerable due to its position in the ankle joint.
C. Fracture of the calcaneus (C) refers to the heel bone, which is less likely to be injured as compared to the talus due to its larger size and more stable position in the foot.

**Clinical Pearl:** Sudden dorsiflexion of the foot can lead to various tarsal bone injuries, with the most common being a fracture of the talus (talar neck fracture). This injury is often seen in sports or traumatic events where dorsiflexion forces are applied to the foot, resulting in a fracture of the talus bone. Understanding the anatomy and biomechanics of the ankle joint is crucial for identifying and appropriately managing these injuries.