理解的对吗？

Subungual haematoma: Red, purple or grey–brown discoloration of the nail plate, usually of the big toe, is usually caused by trauma, although a history of trauma may not be clear. The main differential is subungual melanoma, although rapid onset, lack of nail- fold involvement and proximal clearing as the nail grows indicate haematoma. If there is diagnostic doubt, a biopsy may be needed.

甲下血肿：甲板（通常为大脚趾）的红色、紫色或灰棕色变色通常由创伤引起，但创伤史可能不明确。主要区别是甲下黑色素瘤，虽然两者都可迅速发病，但缺乏甲襞受累和甲生长时近端颜色消失提示血肿。如果存在诊断疑问，可能需要进行活检。