A nail condition in which blood clots form under the nail plate due to a small injury of the nail plate is:

The condition described is accurately identified as bruised nails. This condition occurs when blood vessels beneath the nail plate are damaged, typically due to a minor trauma or injury. As a result, blood pools between the nail plate and the underlying nail bed, creating a dark discoloration that can resemble a bruise.

Bruised nails often present with a dark red or black appearance and may be accompanied by some discomfort or pain, particularly in the case of a significant impact. Understanding this condition is essential, as it can also serve as an indicator for more severe underlying issues or help in assessing the extent of an injury.

The other answer options do not specifically define the condition associated with blood clots under the nail plate. For instance, blue nails can refer to various causes, including circulation issues, but do not specifically denote the local bruising from an injury. Similarly, bruised onychia refers to inflammation or trauma affecting the nail fold rather than the nail plate itself. Abnormal nails is a broad term that lacks specificity and could refer to many nail disorders, not just localized hematomas under the nail. Therefore, bruised nails is the most precise and accurate term for this particular condition.