**Core Concept**
Patterned abrasion is a type of injury that occurs when a person's skin comes into contact with a foreign object, in this case, the tyre of an auto rickshaw. The tyre's surface pattern is transferred to the skin, resulting in an abrasion that mirrors the pattern of the object. This type of injury is particularly useful in forensic medicine as it can provide valuable information about the circumstances surrounding the injury.

**Why the Correct Answer is Right**
When an auto rickshaw ran over a child's thigh, the tyre's surface came into contact with the skin, causing friction and resulting in an abrasion. The pattern of the tyre's tread was transferred to the skin, creating a patterned abrasion. This type of injury is characterized by the presence of a distinct pattern that corresponds to the surface of the object that caused the injury. In this case, the tyre's pattern is visible on the child's thigh, making it an example of a patterned abrasion.

**Why Each Wrong Option is Incorrect**
**Option A:** Patterned bruise refers to an injury that is characterized by a bluish discoloration of the skin, typically caused by blood leakage into the tissues. This type of injury does not involve the transfer of a pattern to the skin.

**Option C:** Pressure abrasion is a type of injury that occurs when the skin is subjected to intense pressure, resulting in the removal of the top layers of skin. While pressure abrasions can be caused by a variety of objects, they do not typically involve the transfer of a pattern to the skin.

**Option D:** Graze abrasion is a type of injury that occurs when the skin is scraped against a rough surface, resulting in the removal of the top layers of skin. Graze abrasions can be caused by a variety of objects, but they do not typically involve the transfer of a pattern to the skin.

**Clinical Pearl / High-Yield Fact**
It's essential to note that patterned abrasions can provide valuable information about the circumstances surrounding an injury, including the type of object that caused the injury and the direction of force. This can be particularly useful in forensic medicine, where the goal is to reconstruct the events surrounding an injury.

**✓ Correct Answer: B. Patterned abrasion**