Final answer:
The correct documentation for a linear crack from the epidermis to the dermis at the corner of the mouth is a fissure. It is not a scar, atrophy, or excoriation.
Step-by-step explanation:
A linear crack extending from the epidermis to the dermis typically located at the corner of the mouth is described medically as a fissure. This type of skin lesion is characterized by a break, slit, or narrow opening that can be caused by a variety of factors, including dryness or an underlying health condition. It is not a scar, which is fibrous tissue that replaces normal tissue after an injury; atrophy, which is thinning or shrinking of tissues; or an excoriation, which is an area where the skin has been picked away or rubbed off.