Finger Clubbing: A quantitative survey by analysis of the shadowgraph.

Finger-clubbing has been measured from the magnified silhouette of the right index 
finger (shadowgram) in 125 subjects, comprising children and young adults. The 
profile and hyponychial angles were both found to be good discriminators 
of clubbing and to be independent of age and sex. The 
normal profile angle was 168.3 degrees +/- 3.6 and the mean 
normal hyponychial angle was 180.1 degrees +/- 4.2. Patients with cystic 
fibrosis and cyanotic congenital heart-disease were found to have grossly elevated 
values of these angles. Some asthmatics were found to have a 
moderate degree of clubbing with significantly elevated values of these angles. 
The shadowgram proved a convenient objective method for recording the degree 
and progress of fingerclubbing in clinical practice. 