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Flexor digitorum longus




Flexor digitorum longus - posterior view
Flexor digitorum longus - foot - inferior view
Flexor digitorum longus - posteromedial view

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page


  • Deep


  • Middle 1/3 of the posterior part of tibia
  • Adjacent fascia of tibialis posterior


  • Plantar side of base of 2-5 distal phalanx

Main function

  • MTP-joint
    • Flexion
  • PIP-joint
    • Flexion
  • DIP-joint
    • Flexion

Secondary function

  • Ankle
    • Plantar flexion
  • Tarsal joint
    • Inversion

Nerve innervation

  • Segmental
    • L5-S2
  • Peripheral
    • Tibial nerve

Arterial supply

  • Posterior part of the tibial artery

Palpation of the distal tendon

  • Patient position
    • Supine
  • Place your one hand on the posterior aspect of the medial malleoli
  • There are 3 tendons located here
    • Tibialis posterior
    • Flexor digitorum longus
    • Flexor hallucis longus
  • Ask the patient to flex the toes (not the big toe), and feel for the tendon which increases it's tension

Strength test

  • Patient position
    • Supine
  • Stagilize the patient's foot by holding around the metatarsals while the foot is held in a neutral position
  • Use the tips of opposite hand to give resistance under the 2-5 distal phalanx of the patient, press in an extension direction so that the patient is giving force towards flexion of the toes