Sinus Tarsi

Description

Tarsal sinus (eye of the foot) A. Schematic presentation of the bones forming the subtalar joint and sinus tarsi, Nav – os naviculare.; B. X-ray imaging (lateral view) of the tarsal sinus. C. MRI of the subtalar joint, sinus tarsi and ligaments – ITCL – Interosseal talocalcaneal ligament, CL – Cervical ligament, M – Medial root of the inferior extensor retinaculum (IER)

Retinacular bands in the sinus tarsi. (a) Schematic drawing illustrates the arrangement of the lateral (void arrowheads), intermediate (black arrowheads), and medial (arrows) roots of the oblique inferolateral arm of the inferior extensor retinaculum. The medial root forms a sling around the tendinous slips of the extensor digitorum longus tendons and attaches into the talus (a, b) and calcaneus (c, d) by means of multiple bands (a-d). The intermediate root has a selective insertion into the calcaneus, whereas the lateral root bridges over the sinus reinforcing the inferior peroneal retinaculum on the lateral aspect of the calcaneus. More dorsally, the inferior extensor retinaculum also stabilizes the tibialis anterior (TA) and the extensor hallucis longus (EHL) tendons. (b) Short-axis US image of the inferior extensor retinaculum forming a sling around the extensor digitorum longus tendon (EDL). High-resolution ultrasound identies the layers of the inferior extensor retinaculum (void arrowhead) from which its medial (arrows) and intermediate (white arrowhead) roots detach. (c) Coronal US image of the sinus tarsi reveals the medial and intermediate roots as they cross the sinus groove and insert on the talus and calcaneus (asterisk). Their oblique orientation causes posterior acoustic attenuation and a heterogeneous appearance of fat. Note the lateral root (void arrowheads) bridging over the sinus.

Names

• Sinus Tarsi
• Tarsal Sinus
• Talocalcaneal sulcus

General

• Cylindrical canal in the lateral hindfoot, distal and slightly anterior to lateral malleolus
• Complex anatomical structure with multiple ligaments and adipose fat pad
• Tarasl Canal opens up into the sinus tarsi

Gross Anatomy

• Location: hindfoot
• Contained by
  • Calcaneus
  • Talus
  • Talocalcaneonavicular Joint
  • Bottom of the subtalar joint
• Ligaments:
  • Inferior Extensor Retinaculum: intermediate, medial and lateral roots
  • Cervical Ligament of the Foot
  • Interosseous Talocalcaneal Ligament
• Pad of adipose tissue

Function

• Helps stabilize the ankle
• Cervical ligaments limit inversion
• Interrous talocalcaneal ligament limits eversion

Imaging

• MRI is the imaging modality of choice when evaluatiing the sinus tarsi

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Clinical Significance

Pathology

• Sinus Tarsi Syndrome

Procedural

• Sinus Tarsi Injection

Surgical Considerations

• Surgical approach for Calcaneus Fracture

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See Also

• Ankle Pain Main
• Physical Exam Ankle
• Ankle Anatomy Main

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