The mechanism of injury of transverse fracture of medial malleolus results due to
**Transverse Fracture of Medial Malleolus**
### Core Concept
A transverse fracture of the medial malleolus occurs due to a direct blow to the medial aspect of the ankle, resulting in a fracture through the weight-bearing portion of the tibia. This type of fracture is often associated with a bimalleolar or trimalleolar fracture pattern, indicating significant ankle instability.
### Why the Correct Answer is Right
The direct blow to the medial aspect of the ankle causes a compressive force to be applied across the tibia, resulting in a transverse fracture line. The medial malleolus is a weak point in the ankle mortise, and this type of force can easily disrupt the cortical bone in this area. The deltoid ligament, which attaches to the medial malleolus, may also be torn or stretched.
### Why Each Wrong Option is Incorrect
**Option A:** This option is incorrect because a transverse fracture of the medial malleolus is typically caused by a direct blow, not a twisting or rotational force. While a twisting force can cause a different type of fracture, it is not the mechanism of injury for a transverse fracture.
**Option B:** This option is incorrect because an avulsion fracture of the medial malleolus would be caused by a force that pulls the bone away from the surrounding ligaments, rather than a direct blow.
**Option C:** This option is incorrect because a comminuted fracture of the medial malleolus would be caused by a more complex mechanism of injury, such as a high-energy trauma or a fall from a height.
### Clinical Pearl / High-Yield Fact
It is essential to remember that a transverse fracture of the medial malleolus is often associated with significant ankle instability and may require surgical intervention to restore the normal anatomy and function of the ankle joint.
### Correct Answer: A. Direct blow to the medial aspect of the ankle.