Pterygium of the nail can occur at which of the following parts?

Pterygium of the nail refers to a condition where there is an abnormal growth of tissue that can occur in specific areas surrounding the nail. The eponychium, which is the live tissue at the base of the nail, is particularly susceptible to pterygium formation, often as a result of trauma or certain skin conditions.

The hyponychium, located under the tip of the nail, can also be involved, but it is not the primary site for pterygium. The emphasis is on the eponychium, which serves as a junction between the nail and the surrounding skin, making it a crucial area for this condition.

Understanding why pterygium primarily affects these areas helps in recognizing the relationship between external factors and nail health. The hyponychium and eponychium, having a protective function for the nail, can be sites of irritation that lead to pterygium development under certain conditions. This aligns well with the common clinical presentation of pterygium, thus establishing why the answer focusing on these areas is correct.