Table 1.

The Classifications of FPL Anomalies

Five groups

1. Conjunction with radial deficiency

2. Conjunction with hypoplasia of the thumb

3. Conjunction with absence of the median innervated intrinsic muscles

4. Conjunction with absence of the flexor pollicis brevis

5. Simple abnormalities of the flexor pollicis longus alone

Four subgroups

i. Absence

ii. Abnormal connection

iii. Anomalous insertion

iv. Abnormal course