Flexor Digitorum Longus Tendon Under The Skin, Plantar View

Description

Arising from the posterior compartment of the leg and entering the sole deep to the flexor retinaculum, the flexor digitorum longus (FDL) tendon is traced in a plantar (inferior) view beneath the skin as it courses anteriorly toward the digits. At the midfoot it lies medial to the quadratus plantae and is crossed by the flexor hallucis longus tendon at the chiasma plantare (knot of Henry), then divides into four distal slips for toes 2 through 5. Each terminal tendon runs along the plantar aspect of the corresponding digit, passing deep to the fibrous digital sheath to insert on the plantar base of the distal phalanx, with the lumbricals arising from the medial sides of the FDL tendons. This plantar perspective matters because it clarifies how FDL contributes to toe flexion at the distal interphalangeal joints while also acting as a dynamic support for the longitudinal arches through its long moment arm under the midfoot. Small changes in tendon balance show up clinically. Claw toe and hammer toe deformities are often discussed in terms of overpowering long flexors, and the relationship of FDL to the tarsal tunnel contents helps explain plantar foot pain patterns when the tibial nerve is compressed or when tenosynovitis is present. In teaching, the composition works well for lower-limb anatomy labs, podiatry and orthopedic lecture slides on the plantar compartments, and surgical atlases describing tendon transfer techniques such as FDL transfer for posterior tibial tendon dysfunction. It also supports patient-education graphics explaining tendon irritation in runners or diabetics with forefoot overload. Anatomical accuracy verified by SciePro's Medical Advisory Board.