| Accessory Navicular Type | Incidence | Anatomy | Symptoms | Treatment Approach |
|---|---|---|---|---|
| Type I (os tibiale externum) | ~30% of AN cases | Small sesamoid in posterior tibial tendon | Usually asymptomatic | Rarely symptomatic; conservative only |
| Type II (synchondrosis) | ~50–60% of AN cases | Connected to navicular via fibrocartilage | Most commonly symptomatic type | Conservative → Kidner procedure |
| Type III (cornuate navicular) | ~10–20% of AN cases | Fused to navicular (large navicular) | Shoe pressure, arch pain | Shoe modification, custom orthotics |
| Treatment | Success Rate | Recovery | Best For |
|---|---|---|---|
| Activity modification + supportive shoes | 40–60% (mild cases) | Immediate | Mild symptomatic, acute flare |
| Custom orthotics (medial arch) | 60–75% | 4–6 weeks | Type II with flat foot component |
| Cast immobilization (4–6 wks) | 60–70% (short-term) | 6–8 weeks | Adolescent, acute irritation |
| Corticosteroid injection | 50–65% | Days–weeks | Acute bursitis flare over prominence |
| Kidner Procedure (excision) | 85–90% | 6–8 weeks NWB then PT | Failed conservative; Type II |
Quick answer: Accessory Navicular Os Naviculare Michigan Podiatrist is a common foot/ankle topic that affects many patients. The 2026 evidence-based approach combines proper diagnosis, conservative-first treatment, and escalation only when needed. We treat this regularly at our Howell and Bloomfield Hills practices. Call (810) 206-1402.
Medically reviewed by Dr. Tom Biernacki, DPM
Board-certified podiatric surgeon | Balance Foot & Ankle
Last reviewed: May 2026
It sounds alarming when a podiatrist points to an X-ray and says, “You have an extra bone in your foot.” But the os naviculare — medically known as the accessory navicular or os tibiale externum — is not a disease, not a fracture, and not something that just developed. It has been there since you were a child. The question is simply: why is it causing problems now?
The most important clinical decision with Accessory Navicular Os Naviculare Michigan Podiatrist isn’t which treatment to start with — it’s identifying the correct subtype. That changes everything. Call (810) 206-1402.
What Is the Os Naviculare?
The os naviculare (Latin: “little boat bone”) is an accessory ossicle — a small, extra piece of bone that develops when a secondary ossification center in the navicular fails to fully fuse during skeletal growth between ages 9 and 16. It sits on the medial (inner) side of the midfoot, creating a bony prominence that is visible on X-ray and often palpable on physical exam. It affects roughly 1 in 10 people, making it the most commonly occurring extra bone in the human foot.
There are three anatomical types. Type I: a small free ossicle within the posterior tibial tendon — usually asymptomatic. Type II: connected to the navicular by a fibrocartilage bridge (synchondrosis) — the most symptomatic type, responsible for the majority of patients we see. Type III: a fully fused extra prominence on the navicular tuberosity — typically causes symptoms only from direct shoe friction rather than tendon stress. Our treatment approach varies significantly by type, which is why proper classification at diagnosis matters.
Key takeaway: The os naviculare has been in your foot your entire life. Symptoms begin when repetitive stress, a new activity, or a sprain overloads the fibrocartilage junction connecting it to the main navicular bone.
Symptoms and Who Gets Them
The os naviculare most commonly becomes symptomatic during adolescence (ages 10–15, particularly in girls during growth spurts) or in adulthood after a new activity, prolonged standing, or an ankle sprain. The symptoms are specific and predictable: a painful, tender bump on the inner midfoot, arch aching that worsens with activity and improves with rest, and pain triggered by direct shoe pressure over the prominence. Flat-footed patients are at higher risk because overpronation constantly loads the posterior tibial tendon — which inserts directly at or near the os naviculare.
- Inner foot bump — visible or palpable, sometimes with overlying redness from shoe friction
- Medial arch aching — worsens through the day, improves overnight with rest
- Pain during and after athletic activity — running, basketball, soccer, dance
- Sharp pain after ankle sprains — acute disruption of the synchondrosis
- Difficulty fitting into normal shoes — the prominence alters the foot’s width in the midfoot region
How We Diagnose It
Diagnosis starts with weight-bearing X-rays of the foot, which immediately reveal the os naviculare and allow us to classify its type. We assess arch height, posterior tibial tendon function (single-heel-rise test), and identify any skin changes over the prominence. For Type II cases where surgery is being considered or when the posterior tibial tendon’s integrity is in question, MRI is ordered. MRI reveals synchondrosis edema (a reliable marker of which patients will fail conservative treatment), posterior tibial tendon tears or attenuation, and any associated spring ligament injury. Bone scan is occasionally used in pediatric patients when MRI is not immediately available.
The key differentials we rule out: navicular stress fracture (distinct fracture line on MRI vs. smooth ossicle margins), posterior tibial tendon dysfunction, tarsal coalition, and Köhler disease in children.
Treatment at Our Michigan Clinic
Our treatment philosophy is conservative-first, with a clear threshold for escalation. Approximately 60–70% of patients achieve lasting relief without surgery when given a proper conservative program.
- Custom orthotics — the most impactful single intervention; controls overpronation to unload the posterior tibial tendon and reduce synchondrosis stress
- Supportive footwear — wide medial toe box, built-in arch support, soft shoe counter; avoid stiff dress shoes and minimalist footwear
- Activity modification — reduce provoking activities for 4–6 weeks to allow synchondrosis inflammation to resolve
- Physical therapy — posterior tibial tendon strengthening, single-leg balance, eccentric calf exercises, gait retraining
- Immobilization boot — for acute synchondrosis injuries after a sprain, 4–6 weeks in a CAM walker
- Cortisone injection — a single injection near the synchondrosis for persistent inflammation that does not respond to activity modification alone
- Kidner procedure — when 3–6 months of comprehensive conservative care fails; removes the os naviculare and reconstructs the posterior tibial tendon attachment; 85–95% satisfaction rate
Key takeaway: In children and adolescents, the synchondrosis has the best healing potential. Conservative treatment including orthotics and activity modification succeeds at a higher rate in younger patients — we only recommend surgery in adolescents after genuine failure of a full conservative program.
⚠️ When to see a podiatrist:
- Medial arch pain that is worsening despite orthotics and activity modification for 3+ months
- Inability to perform a single-heel-rise on the affected side — posterior tibial tendon weakness
- Significant swelling, redness, or skin breakdown over the inner arch prominence
- Pain in a child or teenager that is causing a limp or preventing participation in sports
- Acute worsening of inner foot pain after an ankle roll or twist
- Flat foot deformity that seems to be progressing — possible posterior tibial tendon dysfunction
Frequently Asked Questions
Is the os naviculare the same as a navicular bone spur?
No. A bone spur is an overgrowth of existing bone in response to stress. The os naviculare is a separate, distinct bone that formed during fetal development and has always been present. On X-ray, it appears as a separate ossicle adjacent to the navicular, with smooth, well-corticated margins — distinguishing it from a fracture (irregular margins) or a bone spur (continuous with the parent bone).
Do I need surgery for os naviculare pain?
Most patients do not — approximately 60–70% achieve lasting relief with conservative care. Surgery (the Kidner procedure) is considered when 3–6 months of comprehensive conservative management, including consistent custom orthotics and physical therapy, fails to provide adequate pain relief and functional improvement. When surgery is indicated, outcomes are reliably excellent with 85–95% patient satisfaction.
The Bottom Line
The os naviculare is a common anatomical variant that becomes symptomatic in a predictable way and responds well to treatment. The key is an accurate diagnosis, a proper conservative trial with custom orthotics and physical therapy, and a clear escalation plan if conservative care fails. We treat this condition regularly at Balance Foot & Ankle — if you have inner foot pain or a bump on the medial arch, call us at (810) 206-1402 for a same-day appointment in Howell or Bloomfield Hills, Michigan.
Sources
- Sella EJ, Lawson JP, Ogden JA. “The accessory navicular synchondrosis.” Clin Orthop Relat Res. 1986.
- Chiu NT, et al. “Symptomatic and asymptomatic accessory navicular bones.” J Foot Ankle Surg. 2020.
- Nakayama S, et al. “Bone scintigraphy in symptomatic accessory navicular.” J Nucl Med. 1993.
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Frequently Asked Questions
When should I see a podiatrist?
If symptoms persist past 2 weeks, affect your normal activity, or are accompanied by red-flag symptoms (warmth, redness, swelling, inability to bear weight).
What does treatment cost?
Most diagnostic visits and conservative treatments are covered by Medicare and major insurers. Out-of-pocket costs vary by your specific plan.
How quickly can I get an appointment?
Most non-urgent cases see us within 5 business days. Urgent cases (sudden pain, possible fracture) typically same or next business day.
What is Foot pain?
Foot pain is a common foot/ankle condition that affects mobility and quality of life. Understanding the underlying cause is the first step in successful treatment. Our podiatrists at Balance Foot & Ankle perform a hands-on biomechanical exam, review your activity history, and use diagnostic imaging when appropriate to identify the root cause—not just treat the symptom. Many patients have been told to “rest and ice” without a deeper diagnostic workup; our approach is different.
Symptoms and warning signs
Common signs of foot pain include pain that worsens with activity, morning stiffness, swelling, tenderness when palpated, and difficulty bearing weight. If you experience sudden severe pain, inability to walk, visible deformity, numbness or color change, contact our office the same day or visit urgent care—these can signal a more serious injury such as a fracture, tendon rupture, or vascular compromise. Diabetics with any foot wound should seek same-day care.
Conservative treatment options
Most cases of foot pain respond to non-surgical care: structured rest, supportive footwear changes, custom orthotics, targeted stretching and strengthening protocols, anti-inflammatory medications when medically appropriate, and in-office procedures such as ultrasound-guided injections. We also offer advanced therapies including MLS laser therapy, EPAT/shockwave, regenerative injections, and image-guided procedures. Treatment is sequenced from least invasive to most invasive, and we explain the rationale at every step.
When is surgery considered?
Surgery is reserved for cases that fail 3-6 months of well-structured conservative care, when there is structural pathology (severe deformity, complete tear, advanced arthritis), or when imaging shows damage that will not heal without intervention. Our surgeons have performed 3,000+ foot and ankle procedures and prioritize minimally-invasive techniques whenever appropriate. We discuss recovery timelines, return-to-activity milestones, and realistic outcome expectations before any procedure is scheduled.
Recovery timeline and prevention
Recovery from foot pain varies based on severity and chosen treatment path. Conservative cases often improve within 4-8 weeks with consistent adherence to the protocol. Post-procedural recovery may range from a few days (in-office procedures) to several months (reconstructive surgery). Long-term prevention involves footwear assessment, activity modification, structured strengthening, and regular check-ins with your podiatrist if you have a history of recurrence. We provide written home-exercise plans and digital follow-up support.
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Dr. Tom Biernacki, DPM is a board-certified foot & ankle surgeon (ABFAS & ABPM) at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has made him one of the most-followed foot & ankle educators on YouTube.