Clubbing Due to Emphysema

Clubbing is classically associated with pulmonary disease, although it can be associated with other conditions, including, of all things, Graves Disease.  The association of vitiligo and clubbing  may make you think of Grave's, but in this particular case it was a red herring.  It was just garden-variety COPD and vitiligo.  Similar appearance is seen in a condition known as hypertrophic pulmonary osteoarthropathy, which can have a destructive arthritic condition as well.  For those of you who have read this far, what is the name of the angle between the nail and the digit, for one point?