What type of nails does 'onychorrhexis' refer to?

Onychorrhexis refers specifically to brittle nails, which are characterized by longitudinal ridges and a tendency to split or break easily. This condition often arises due to various factors, such as environmental exposure, overuse of nail products, or underlying health issues. Recognizing onychorrhexis is important in a cosmetology context because it can influence the type of nail care and treatments that are recommended for clients.

In contrast, the other options do not correctly describe onychorrhexis. Nails with ridges can exist in both healthy and unhealthy states and do not exclusively indicate brittleness. Normal healthy nails typically exhibit smoothness and strength, while long nails are merely a description of size without any implication of brittleness or structural integrity.