Longitudinal Grooves

Longitudinal depressions can occur in the nail as a result of a space-occupying lesion in the nail fold overlying the nail matrix. The mass presses on the matrix and nascent nail resulting in a depressed deformity. Lesions such as myxoid cyst (Figure 14) and fibroma (Figure 15) can cause the groove. When the mass is removed, the nail usually grows in normally (see myxoid cyst).