Knot of Henry: Role in Tendon Transfer

Abstract

The term “Master knot of Henry” refers to the site of cross connections between long (extrinsic) tendons of foot namely Flexor Digitorum Longus Tendon (FDLT) and Flexor Hallucis Longus Tendon (FHLT). This chiasmatic structure in the second layer of sole, was first described by Henry in 1940. Over the years it has gained importance because of its close association with surgical procedures such as ‘Tendon Transfers’, whereby insertion of a muscle-tendon unit is relocated at another site for restoration of lost function. The demand for these surgical procedures is constantly increasing in parallel with increasing number of irreparable nerve injuries, spinal cord injuries and road traffic accidents etc. Both FDLT and FHLT are identified as potential tendon transfer candidates and variations of cross connections between FDLT and FHLT at Henry’s knot have been reported. In the majority of cases, slips proceeding from FHLT to FDLT have been observed. However, we observed the presence of two variant tendinous slips extending from the FDLT to FHLT, one lying proximal and the other distal to the chiasmatic crossover, in left foot of a male cadaver. Awareness regarding possible variations with context to the cross pattern at the knot could be the determining factor in deciding about the preferential tendon transfer candidate with maximal preservation of functioning of hallux as well as other little digits.

Keywords

• chiasma tendon
• flexor digitorum longus
• flexor hallucis longus