Study on Tendinous Connections Between Flexor Hallucis Longus and Flexor Digitorum Longus

Abstract

Flexor Hallucis Longus (FHL) and Flexor Digitorum Longus (FDL) are long flexors of the toes, often with the interconnecting tendinous slips at various points. These interconnecting slips hold great significance in reconstruction surgeries of ankle and foot such as chronic Achilles tendon rupture, posterior tibial tendon dysfunction (PTTD) and peroneal tendon rupture. In view of the above this study was aimed to find out various types of connections between tendons of FHL & FDL.Materials and methods: This cross sectional study was carried out in the Department of Anatomy ACSR Government Medical College, Nellore, conducted in a total of 34 lower limbs. Flexor digitorum brevis and abductor hallucis muscles were reflected distally after the removal of the skin, superficial fascia and plantar aponeurosis to expose FHL and FDL tendons which were examined for the interconnections. Specimens with interconnections were photographed and documented.Result: Out of 34 samples, 17 were right sided and 17 were of left sided. Mean foot length was 22.4 ± 1.9 cm. Three types of connections i.e. type 1, 4 & 5 were documented at 17 (50%), 16 (47.1%) and 1 (2.9%) type 5 respectively. Type 1 tendinous connections were further classified into 3 sub types i.e. type 1A were 10 (58.8%), type 1B were 5(29.4%) and type C were of 2(11.8%). Conclusion:This study finds maximum distribution of type1 interconnections followed by type 4 and sub type 1A among type 1. This study also reports for the first time a common origin of 1 st lumbrical from distal part of tendinous slip as well as from 1 st digital slip of FDL. These interconnections provide stable base and enhanced propulsion by toes and also act as natural tenodesis.

Four Tendinous Slips of Flexor Hallucis Longus Tendon: A Case Report

“…In the case of our cadaveric dissection, maintenance of some level of flexion could have been maintained in digits two to five. This is highly relevant in scenarios where preserving dexterity and mobility in the lateral toes is of utmost importance, such as in athletes or certain individuals with specific occupational demands [ 13 ]. These tendinous expansions act as a backup mechanism, allowing the intact tendon to compensate for the loss of function in the injured or lacerated one.…”