[Trigger hallux--a rare cause of pain at the inner malleolus]

Characteristic for a trigger-hallux is a thickening of the m. flexor hallucis longus tendon combined with partial rupture of the central fibers proximal to the tarsal tunnel. Division of the retinaculum flexorum leads to free tendon movement and prevents further tendon degeneration. The course of an 11-years old girl is reported. An effective treatment is established by a simple surgical procedure.