Hallux saltans: the flexor hallucis longus triggering phenomena

Triggering of the toes - hindering the normal tendon motion during flexion and ultimately leading to entrapment - is relatively uncommon, but happens, and involves predominantly the flexor hallucis longus (FHL) tendon. Some authors refer to this condition as "hallux saltans" (HS). The FHL is often entrapped at the ankle or distal third of the leg as it courses between the medial and lateral tubercles of the talus and enters the fibro-osseous groove located medial and inferior to the sustentaculum tali. Martinez-Salazar et al. (2018) state in their case report that dynamic ultrasound provides valuable information in the assessment of HS. This includes identification of focal tendon abnormality and potential sources of mechanical blocking, as well as guiding surgical management.