Pincer nails, also known as trumpet nails or omega nails, are a condition in which the nails curve inward, creating a pinched or triangular shape. Pincer nails can be caused by a variety of factors, including genetics, trauma, and certain medical conditions. While pincer nails are generally harmless, they can be uncomfortable and may make it difficult to perform certain tasks. Treatment options include trimming the nails and wearing wider shoes to reduce pressure on the toes.