Accessory Muscles Around the Ankle Joint - An Anatomical Investigation.

BACKGROUND: Despite their rare occurrence, accessory muscles around the ankle joint may lead to chronic ankle pain, compression neuropathies, hindfoot deformities or impingement syndrome. The aim of this study was to examine their prevalence and morphology. METHODS: A total of 200 lower extremities were included in this given study. The extensor, peroneal, superficial and deep flexor compartments were dissected carefully and assessed regarding the presence of accessory muscles/tendons. In cases of variations, these were evaluated in detail concerning their origins/insertions and course. Distances between the lateral, respectively medial malleolus (depending on the location of the accessory muscle) and the proximal and distal borders of the singular muscle bellies were evaluated. RESULTS: Accessory muscles were present in 12.5% (25/200) of the included specimens (12 female and 11 male body donors). In two individuals, variations were present bilaterally. Muscles were assessed at the medial (accessory flexor digitorum longus & tibiocalcaneus internus), lateral (accessory peroneal, peroneus digiti minimi & peroneus quartus) and ventral (tibioastragalus anticus muscle of Gruber) aspect of the ankle joint. CONCLUSIONS: The current study provides an overview on the prevalence of accessory muscles around the ankle. These data may assist surgeons in anticipating the possible intraoperative presence of these variants.