Flexor Retinaculum of the Ankle

Description

Medial view of the ankle joint presenting the contents of the tarsal tunnel; tibialis posterior tendon (TP), flexor digitorum longus tendon (FDL), posterior tibial artery (PTA), posterior tibial vein (PTV), tibial nerve (TN) and the tendon of flexor hallucis longus (FHL), deep to the flexor retinaculum (FR)

A, Transverse sonogram obtained at the level of the medial malleolus (MM). The normal FR (white arrowheads) appears as a thin fibrillar structure. B, Transverse sonogram obtained at the level of the MM in a patient with a recent ankle injury. The FR (black arrowhead) appears swollen, hypoechoic, and heterogenous. C, Corresponding axial T1-weighted magnetic resonance image obtained after intravenous gadolinium injection confirms the US findings. D, Transverse sonogram obtained during follow-up at 3 months shows a calcification (curved arrow), the outcome of the trauma. Note disappearance of the subcutaneous edema compared with A. Black arrows indicate the tibialis posterior tendon.

Name

• Flexor Retinaculum of Ankle
• Retinaculum Flexorium Tali
• Flexor Retinaculum of the Foot
• Laciniate ligament
• Internal annular ligament

General

• Strong band of fibers that extends from medial malleolus to calcaneus
  • Proximally, continuous with the deep fascia of the leg
  • Also has an attachment to the plantar aponeurosis, fibers of abductor hallucis
• Forms the roof of the Tarsal Tunnel
• Retains the structures of the tarsal tunnel in place, preventing subluxation/ bowstringing as they pass the ankle joint

Tarsal Tunnel

• The following structures pass inferiorly in the tarsal tunnel
  • Tibialis posterior tendon
  • Flexor digitorum longus tendon
  • Posterior tibial artery and vein
  • Tibial nerve
  • Flexor hallucis longus tendon

---

Clinical Significance

• Tarsal Tunnel Syndrome

---

See Also

• Foot Anatomy Main
• Foot Pain Main
• Physical Exam Foot

---