## **Core Concept**
Cubitus varus, also known as a "gunstock deformity," refers to an abnormal inward angulation of the distal humerus, resulting in a varus deformity of the elbow. This condition often arises from a malunion of a fracture. The **supracondylar fracture of the humerus** is a common cause, particularly in children.

## **Why the Correct Answer is Right**
The correct answer, , is the most common cause of cubitus varus. This type of fracture occurs just above the elbow joint in children and is notorious for potential complications, including malunion leading to cubitus varus. The mechanism behind this deformity involves inadequate reduction or loss of reduction during the healing process of the fracture, leading to a characteristic "gunstock" appearance.

## **Why Each Wrong Option is Incorrect**
* **Option A:** - This option is incorrect because, although fractures of the lateral condyle of the humerus can lead to growth disturbances and deformities, they are less commonly associated with cubitus varus compared to supracondylar fractures.
* **Option B:** - Incorrect because medial epicondylar fractures, while they can cause issues with growth and alignment, are not the most common cause of cubitus varus.
* **Option D:** - This option is incorrect as there is no commonly recognized association of cubitus varus with fractures of the radial head in the context provided.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **supracondylar fractures of the humerus** are the most common type of elbow fracture in children and have a high risk of complications, including cubitus varus if not properly managed. Early recognition and proper treatment of these fractures are crucial to prevent long-term deformities.

## **Correct Answer:** . Supracondylar fracture of the humerus