In some of the reaches, where there is a free margin, we may walk through them.
在某些河段, 有空余的地方, 我们可以步行穿过。
英语百科
Surgical margin
Surgical margin, also known as tumor free margin, free margin, normal skin margin, and normal tissue margin, usually refers to the visible normal tissue or skin margin that is removed with the surgical excision of a tumor, growth, or malignancy.