Digital clubbing in cystic fibrosis: the nails as clues to advanced disease

Digital clubbing in cystic fibrosis: the nails as clues to advanced disease

Supplemental Figure 1: Diagram of Lovibond Angle
The Lovibond angle describes the angle between the nail plate and proximal nail fold. In patients with normal digits, this angle is approximately 160º. In patients with digital clubbing, this angle is >180º.

Supplemental Figure 2: Diagram of Schamroth Sign
The Schamroth sign is considered positive when there is loss of the diamond-shaped window between the nails when the fingernails are opposed.

Supplemental Figure 3: Diagram of DPD/IPD Ratio
A DPD/IPD ratio is obtained by measuring the distal phalangeal depth (DPD) and comparing to the interphalangeal depth (IPD). A ratio <1 is normal, while a ratio ≥1 indicates the presence of digital clubbing.