Snapping phenomenon around the ankle: An anatomy-based review

Ankle snapping occurs when tendons or retinacular structures abruptly move or slip over adjacent anatomical structures, often due to anatomical variations, pathological conditions, or acute injury. This phenomenon can cause pain and discomfort, ranging from mild irritation to debilitating symptoms that potentially disrupt daily activities and athletic pursuits. Considering the anatomy of the ankle, these snapping phenomena can be categorized into four regional groups: (1) Lateral; (2) Medial; (3) Anterior; and (4) Posterior. Lateral ankle snapping, a common occurrence, typically results from peroneal tendon subluxation due to compromise of the superior and inferior peroneal retinacula, or from intrasheath subluxation, characterized by abnormal tendon motion within an otherwise intact retromalleolar groove and retinaculum. Medial ankle snapping primarily affects the posterior tibial tendon and can involve the flexor digitorum longus tendon. Anterior ankle snapping results from abnormal gliding of the tibialis anterior tendon, extensor digitorum longus tendon, peroneus tertius tendon, and inferior extensor retinaculum. Posterior ankle snapping typically involves the plantaris tendon and flexor hallucis longus (hallux saltans). This mini-review comprehensively explores these snapping phenomena and their related pathologies in the foot and ankle, emphasizing the crucial roles of anatomical knowledge, thorough clinical assessment, and appropriate diagnostic and treatment approaches.