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Coexistence of Tripartite Accessory Navicular Bone and Os Subfibulare
George Triantafyllou1, Nikolaos-Achilleas Arkoudis2,3, Christos Koutserimpas4
1Department of Anatomy, School of Medicine, Faculty of Health Sciences, National and Kapodistrian University of Athens, 11527 Athens, Greece.
Diagnostics (Basel, Switzerland)
|June 26, 2026
Summary
This case report details an extremely rare combination of accessory ossicles, specifically an os subfibulare and a tripartite os naviculare. Accurate radiological evaluation is crucial for distinguishing these anatomical variants from fractures.
Area of Science:
- Orthopedics
- Radiology
- Anatomy
Background:
- Accessory ossicles are supernumerary bones that can occur in various locations within the musculoskeletal system.
- While common accessory ossicles like the os naviculare are well-documented, rare combinations and multipartite variants present diagnostic challenges.
Purpose of the Study:
- To report an exceptionally rare co-occurrence of an os subfibulare and a tripartite os naviculare.
- To emphasize the anatomical, clinical, and radiological significance of this unique constellation of accessory ossicles.
Main Methods:
- A 43-year-old female patient underwent multi-detector computed tomography (MDCT) with 1.25 mm slice thickness for suspected fracture evaluation.
- Multiplanar reconstructions (axial, coronal, sagittal) and 3D volume-rendered images were utilized for detailed analysis.
Main Results:
- CT imaging revealed the coexistence of an os subfibulare and a tripartite os naviculare.
- Multiplanar and 3D reconstructions confirmed the presence and specific configuration of these rare accessory ossicles.
Conclusions:
- The simultaneous presence of an os subfibulare and a tripartite os naviculare is an exceedingly uncommon anatomical finding.
- Comprehensive radiological assessment using MDCT and advanced reconstructions is vital for accurate identification and to differentiate these variants from pathological conditions.
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