Sinus Tarsi Syndrome (STS)

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 5 min read
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Article Summary

The sinus tarsi is a tube or tunnel between the talus and the calcaneus bones. Sinus tarsi syndrome is pain or injury to this area. Traumatic injury to the ankle/foot (such as an ankle sprain) or overuse (such as repetitive standing or walking) are the main causes of this syndrome. Sinus tarsi syndrome is believed to occur following a single traumatic event or a series of ankle...

Key Takeaways

  • This article explains Other Names in simple medical language.
  • This article explains ANATOMICAL AND KINESIOLOGICAL CONSIDERATIONS in simple medical language.
  • This article explains Pathophysiology in simple medical language.
  • This article explains Causes in simple medical language.
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Definition

The sinus tarsi is a tube or tunnel between the talus and the calcaneus bones. Sinus tarsi syndrome is pain or injury to this area. Traumatic injury to the ankle/foot (such as an ankle sprain) or overuse (such as repetitive standing or walking) are the main causes of this syndrome. Sinus tarsi syndrome is believed to occur following a single traumatic event or a series of ankle sprains that result in significant injuries to the talocrural interosseous and cervical ligaments. These injuries cause instability of the subtalar joint resulting in excessive supination and pronation movements.

Sinus tarsi syndrome (STS) is a clinical entity characterized by persistent anterolateral ankle pain secondary to traumatic injuries to the ankle. Historically, the etiology of this condition has not been well understood. Recent discussions of STS now describe this entity as primarily an instability of the subtalar joint due to ligamentous injuries that results in a synovitis and infiltration of fibrotic tissue into the sinus tarsi space.,

Other Names

  • Sinus Tarsi Syndrome (STS)
  • Canalis Tarsi Syndrome
  • First described by Denis O’Connor in 1958
  • Most patients present in the 3rd, 4th decade of life (need citation)

ANATOMICAL AND KINESIOLOGICAL CONSIDERATIONS

The subtalar joint is comprised of the articulation of the talus and calcaneus across an anterior, middle, and posterior facet. These facets may have variations in their structure and alignments that will affect the movement and stability of the subtalar joint. Extrinsic and intrinsic ligaments provide static stability for the subtalar joint. Extrinsic ligaments include the calcaneofibular ligament and the deltoid ligament, which also provide stability for the talocrural joint. The talocalcaneal, interosseous, and cervical ligaments are the intrinsic ligaments that provide a strong connection for the calcaneal and talar joint surfaces. Ruptures of the intrinsic ligaments allow increased movement of the subtalar joint that may result in instability.–

The motions of the subtalar joint and the entire rearfoot are complex and have been the subject of extensive study and controversy.,, The osteokinematics of the subtalar joint occur about a triplanar axis to create pronation and supination movements. Supination motions of the subtalar joint create bony stability through the rearfoot and midfoot that is important for propulsive movements through the foot. Pronation motions create increased mobility of the rearfoot and midfoot joints allowing the foot to accommodate to uneven surfaces., During running activities, athletes may weight bear entirely onto the forefoot, with ground reaction forces creating supination and pronation motions that occur from the midfoot into the rearfoot. Ground reaction forces during running create movements through the subtalar joint at a higher rate of acceleration and forces than during walking activities.

The sinus tarsi space is filled with many connective tissues that contribute to the stability and the overall proprioception of the ankle. The space is filled with adipose tissue that serves as a bedding for numerous mechanoreceptors and free nerve endings, which along with the ligaments and muscles provide proprioceptive information on the movement of the foot and ankle., The vascular supply of the sinus tarsi is provided by an anastomosis of the sinus tarsi and tarsal canal arteries. The extensor digitorum brevis muscle attaches to the medial and distal aspect of the sinus tarsi, running over the calcaneocuboid joint towards the toes. The inferior extensor retinaculum lies over the lateral aspect of this space and serves as a covering over the sinus tarsi.

Pathophysiology

  • General
    • Overall poorly understood condition and no widely accepted diagnostic criteria
    • Described as clinical entity characterized by persistent anterolateral ankle pain secondary to traumatic injuries to the ankle
    • Due to instability of the subtalar joint due to ligamentous injuries resulting in synovitis, infiltration of fibrotic tissue into the sinus tarsi space
  • Controversy
    • Although generally accepted as a syndrome, some physicians argue that each case of STS can be attributed to a more specific diagnosis
    • For example, Frey et al. performed subtalar arthroscopy on 14 patients with STS, all of whom were given a more specific diagnosis such as a ligament tear post-operatively
  • Canalis tarsi syndrome
    • A severe variant which can include medial hindfoot pain in addition to the typical lateral symptoms

Causes

  • General
    • Caused by hemorrhage and/or infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation of the synovial recesses of the sinus tarsi
    • With or without tears of the associated ligaments
    • This leads to synovitis, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, infiltration of fibrotic tissues
  • Causes
    • Trauma is the most common cause following a single or a series of ankle sprains[rx]
    • Inflammatory pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">arthritis such as autoimmune joint disease causing infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, pain, and swelling. সহজ বাংলা: রোগপ্রতিরোধ ব্যবস্থার ভুল আক্রমণে জয়েন্টের প্রদাহ।" data-rx-term="rheumatoid arthritis" data-rx-definition="Rheumatoid arthritis is an autoimmune joint disease causing inflammation, pain, and swelling. সহজ বাংলা: রোগপ্রতিরোধ ব্যবস্থার ভুল আক্রমণে জয়েন্টের প্রদাহ।">rheumatoid arthritis, gout, or ankylosing arthritis.
    • Flatfoot deformity, tumors, and soft tissue impingement have also been implicated

Associated Conditions

  • Lateral Ankle Sprain, Medial Ankle Sprain
  • Sinus Tarsi
    • Cylindrical canal located in the hindfoot
    • Bordered by the neck of the talus and anterosuperior calcaneus
  • Sports
    • Dancers
    • Volleyball
    • Basketball players
  • Systemic
    • Overweight individuals
  • Structural
    • Pes Planus
    • Hyper pronation deformities

diagnosis: Differential diagnosis is a list of possible conditions that may explain symptoms. সহজ বাংলা: একই লক্ষণের সম্ভাব্য রোগের তালিকা।" data-rx-term="differential diagnosis" data-rx-definition="Differential diagnosis is a list of possible conditions that may explain symptoms. সহজ বাংলা: একই লক্ষণের সম্ভাব্য রোগের তালিকা।">Differential Diagnosis

  • Fractures & Dislocations
    • Distal Tibia Fracture
    • Distal Fibular Fracture
    • Talus Fracture
    • Calcaneus Fracture
    • Subtalar Dislocation
    • Ankle Fracture (& Dislocation)
    • Peroneal Subluxation
  • Muscle and Tendon Injuries
    • Peroneal Tendon Injuries
    • Achilles Tendonitis
    • Achilles Tendon Rupture
    • Posterior Tibial Tendon Dysfunction
    • Flexor Hallucis Longus Tendinopathy
  • Ligament Injuries
    • Lateral Ankle Sprain
    • Medial Ankle Sprain
    • Syndesmotic Sprain
    • Chronic Ankle Instability
    • Intersection Syndrome Foot
  • Bursopathies
    • Retrocalcaneal Bursitis
  • Nerve Injuries
    • Peroneal Nerve Injury
    • Tarsal Tunnel Syndrome
  • Arthropathies
    • Osteoarthritis of the Ankle
    • Osteochondral Defect Talus
  • Pediatrics
    • Fifth Metatarsal Apophysitis (Iselin’s Disease)
    • Calcaneal Apophysitis (Sever’s Disease)
  • Other
    • Haglunds Deformity
    • Posterior Ankle Impingement Syndrome
    • Sinus Tarsi Syndrome

Diagnosis

Clinical location of the tarsal sinus[4]
  • History
    • Pain localized to the lateral hindfoot (sinus tarsi region)
    • Worse with walking, supination, adduction
    • The sensation of instability when walking, especially on uneven surfaces[5]
  • Physical Exam: Physical Exam Ankle
    • Inspect for Pes Planus
    • Tenderness over the lateral opening of the tarsal sinus
  • Special Tests

Radiographs

  • Standard Radiographs Ankle
  • Findings
    • Osteoarthritis of the subtalar joint
    • Intraosseous cysts

CT

  • Findings
    • Secondary bony changes (earlier than XR)

MRI

  • Imaging modality of choice
    • Lektrakul found high sensitivity with unknown specificity[6]
  • Challenges
    • Oblique course of ligamentous structures in the sinus tarsi makes identifying a specific diagnosis difficult
    • Lee et al: found low agreement between symptomatic MRI and arthroscopy[7]
  • Findings
    • Inflammation
    • Scar tissue formation
    • Ligamentous injuries
  • Ganglion cysts in the region of the sinus tarsi may compress the posterior tibial nerve.

Management

Nonoperative

  • NSAIDS
  • Orthotics/ Inserts
    • Stable shoes
    • Ankle Sleeve
    • Other orthotic
  • Immobilization
  • Cryotherapy

Operative

  • Indications
    • Presence of ganglion cyst
  • Technique
    • Synovectomy
    • Debridement
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Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
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Questions to ask

  • What is the most likely cause of my symptoms?
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Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
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OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
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Avoid these mistakes

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Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
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Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

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Care roadmap for: Sinus Tarsi Syndrome (STS)

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.