First up was the reader's brother whose nails grew to a point, and curved slightly downwards. What does this signify, our reader wondered. It could be an indication of lung problems, according to a reflexologist. In reflexology, the tips of the toes and fingers relate to the sinuses, nasal passages and upper respiratory tract. The abnormal nail growth could suggest the lung condition brochiectasis. Less seriously, it could also indicate a lack of calcium or magnesium - and if it's the toenails that are affected, it could be caused by poorly fitting shoes. On a similar theme, another reader suspects the problem could be associated with tight-fitting socks. Cotton socks can shrink by as much as 30% if they have been tumble-dried. If it's not the socks, and it's not the shoes, curving nails could be caused by trauma, poor circulation or nutritional deficiencies, suggests another reader.