Clin Orthop Surg.  2021 Jun;13(2):261-265. 10.4055/cios20054.

Anatomical Study of the Accessory Tendon of the Extensor Hallucis Longus Muscle and Its Clinical Application

• Li Y
• Zhang JY
• Zhao XY
• Pan LY
• Jin DH
• Xu HX
• Cui HZ
• Liu YQ
• Qin XZ
• Li Q

• KMID: 2515886
• DOI: http://doi.org/10.4055/cios20054

Abstract

Background
The accessory tendon of the extensor hallucis longus (ATEHL) muscle is a common abnormal structure, and its clinical significance remains debatable. In this study, we provide the incidence of the ATEHL and characterize its morphological types in Asian cadavers and investigate its clinical applications.
Methods
The tendons from 50 adult cadaveric feet, fixed in 10% formalin, were analyzed. We measured the length and width of both the ATEHL and the extensor hallucis brevis (EHB).
Results
All dissected specimens had an ATEHL. The first metatarsophalangeal joint was surrounded by an accessory tendon that inserted onto the joint capsule and the dorsal base of the proximal phalanx. We classified the ATEHL into 3 types based on their directions. Differences in ATEHL type based on sex were not statistically significant.
Conclusions
We found an ATEHL in all cadaveric specimens in this study. We surmise that the ATEHL acts as an antagonist with the EHB when the toe is extending, which might help prevent the occurrence of hallux valgus deformity.

Keyword

Accessory tendon; Extensor hallucis longus; Proximal phalanx; Anatomy; Extensor hallucis brevis muscle