Abstract
In this paper, we report a case of a 14-year-old girl with congenital aplasia of the flexor pollicis longus tendon who had no other associated anomalies of thumb hypoplasia and no trauma history. Flexor pollicis longus tendon anomalies are rare; several types of this congenital anomaly have been reported in the literature. The diagnosis should be considered if a patient is unable to flex the interphalangeal joint of the thumb. A hypoplastic thumb or an absent interphalangeal joint crease may be a diagnostic feature in such cases. Besides physical examination, we also used direct radiography and magnetic resonance imaging to diagnose this rare congenital anomaly in our patient.