Accessory flexor digitorum longus muscle

The accessory flexor digitorum longus muscle is an accessory muscle in the deep posterior compartment of the leg with a reported prevalence of 6-8%. Unilateral muscles are more common although bilateral cases have been reported.

  • origin: variable; either the medial margin of the tibia and deep posterior compartment fascia; or the fibula1,3
  • insertion: variable; either the quadratus plantae, tendon of flexor digitorum longus or both 1,3

The accessory flexor digitorum longus muscle arises from the medial margin of the tibia and the deep posterior compartment fascia or from the fibula. Its insertion may occur into the quadratus plantae muscle, tendon of flexor digitorum longus or both.

The accessory flexor digitorum longus muscle may compress the neurovascular bundle within the tarsal tunnel and cause tarsal tunnel syndrome 1,3. The accessory flexor digitorum longus muscle has also been reported to contribute to the development of flexor hallucis longus tenosynovitis 4.

Anatomy: Lower limb
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Article information

rID: 63968
Section: Anatomy
Synonyms or Alternate Spellings:

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