Clubbing

Today in morning report we discussed a patient, who among other problems, was clubbed.

Clubbing is the enlargement of the terminal segments of the fingers and/or toes that results from the proliferation of the connective tissue between the nail matrix and the distal phalanx. It develops in the context of a number of neoplastic, infectious, inflammatory and vascular conditions.

Features on physical exam that make clubbing more likely include changes in nail-fold angles, as well as changes in the shape, depth, and width of the terminal phalanges.

1) Phalangeal Depth - This ratio compares the depth of the distal phalanges to the inerphalangeal areas. Normally, this is less than 1. Once this ratio exceeds 1, clubbing is more likely.

2) Nail Fold angles - Two angles are commonly discussed: the profile angle and hyponychial angle.

a) The profile angle can be estimated by the angle the nail projects from the nail fold. normally this is about 160 degrees but exceeds 180 degrees when the finger is clubbed.

b)The hyponychial angle compares two lines, (1), from the DIP joint to the nail fold and (2), from the nail fold to the point where the nail meets the finger tips. This angle is should not exceed 190 degrees normally and if it does, clubbing is likely present.

3) Nail bed squishiness - Palpation of the nail bed in clubbed fingers tends to be spongier than a normal nail with the sensation that the nail is floating.

Check out the JAMA rational clinical exam series here for an evidence based review.