Hippocratic fingers (Nail clubbing)

Clubbing (nail clubbing or Hippocratic fingers ) is a deformity of the fingers and fingernails, with changing of the distant finger phalanges into the form of a drumstick or fingernails into the form of a watch-glass presents a well-known clinical phenomenon that suggests the presence of various diseases, especially those associated with hypoxia, mostly of the heart and lungs.

Source:
http://www.nlm.nih.gov/medlineplus/ency/article/003282.htm
http://emedicine.medscape.com/article/1105946-overview