title: Anatomical study of toe flexion by flexor hallucis longus.
abstract: Because connections exist between the flexor hallucis longus (FHL) and flexor digitorum longus (FDL), the FHL is surmised to exert a flexion action on the lesser toes, but this has not been studied quantitatively. The objectives of this study have thus been to clarify the types of FHL and FDL connections and branching, and to deduce the toe flexion actions of the FHL. One hundred legs from 55 cadavers were used for the study, with FHLs and FDLs harvested from the plantar aspect of the foot, and connections and branches classified. Image-analysis software was then used to analyze cross-sectional areas (CSAs) of each tendon, and the proportion of FHL was calculated in relation to flexor tendons of each toe. Type I (single slip from FHL to FDL tendon) was seen in 86 legs (86%), Type II (crossed connection) in 3 legs (3%), and Type III (single slip from FDL to FHL tendon) or Type IV (no connection between muscles) in 0 legs (0%). In addition, Type V (double slip from FHL to FDL tendon) was seen in 11 legs (11%), representing a new type not recorded in previous classifications. In terms of the various flexor tendons, the proportion of FHL showing tendons to toes 2 and 3 was high, at approximately 50-70%. Consequently, considering the branching type and proportion of CSA, the FHL was conjectured to not only act to flex the hallux, but also play a significant role in the flexion of toes 2 and 3. These results offer useful information for future clarification of the functional roles of tendinous slips from the FHL.
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Shimami-cho 1398, Kita-ku, Niigata City, Niigata, 950-3198, Japan; Department of Anatomy, School of Life Dentistry at Niigata, Nippon Dental University, Niigata, 951-8580, Japan. Electronic address: edama@nuhw.ac.jp.
authors.forename: Mutsuaki
authors.initials: M
authors.lastname: Edama
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Shimami-cho 1398, Kita-ku, Niigata City, Niigata, 950-3198, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kubo
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Shimami-cho 1398, Kita-ku, Niigata City, Niigata, 950-3198, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Onishi
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Shimami-cho 1398, Kita-ku, Niigata City, Niigata, 950-3198, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Takabayashi
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Shimami-cho 1398, Kita-ku, Niigata City, Niigata, 950-3198, Japan.
authors.forename: Erika
authors.initials: E
authors.lastname: Yokoyama
authors.affiliation: Department of Rehabilitation, Oguma Orthopedics Clinic, Niigata, 950-2023, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Inai
authors.affiliation: Department of Rehabilitation, Sanjo General Hospital, Niigata, 955-0055, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Rehabilitation, Niigata Medical Center, Niigata, 950-2022, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nashimoto
authors.affiliation: Department of Anatomy, School of Life Dentistry at Niigata, Nippon Dental University, Niigata, 951-8580, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Kageyama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019412:Anatomy, Cross-Sectional; D002102:Cadaver; D005260:Female; D005528:Foot / Q000033:anatomy & histology; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009132:Muscles / Q000033:anatomy & histology / Q000502:physiology; D016059:Range of Motion, Articular; D012727:Sex Characteristics; D013709:Tendon Transfer; D013710:Tendons / Q000033:anatomy & histology* / Q000502:physiology; D014034:Toes / Q000033:anatomy & histology* / Q000502:physiology
keywords: Classification of interconnection; Tendinous slip; Tendon transfer