Radiology Teaching Files > Case 57283169

Last visited 11/08/2011 OS NAVICULARE SYNDROME
Contributed by: Nick Ludwig, Resident, SAMMC, Texas, USA.
Patient: male
History: 29 yo male with medial ankle pain; tender to palpation over the posterior tibialis tendon per podiatry.

Fig. 1: Axial Proton Density

Fig. 2: Axial STIR

Fig. 3: Sagittal Proton Density

Fig. 4: Sagittal STIR
Findings: Os naviculare with navicular pseudoarticulation and underlying bone marrow edema in the ossicle and navicular.
Diagnosis: Os naviculare syndrome


  • Os Navicular; synonym Os Tibiale Externum or Os Naviculare secondarium
  • Three types
    • Type I
      • well defined, round or oval bones measuring 2-3 mm n diameter
      • located up to 5 mm medial and posterior to the medial aspect of the navicular
    • Type II
      • measures 9-12 mm in size
      • lies adjacent to the tubercle of the navicular
      • residual cartilaginous synchondrosis joins the ossicle 1-2 mm posterior and medial to the navicular
      • majority of posterior tibialis inserts on the the type II ossicle
    • Type III
      • Cornuate navicular; prominent navicular tuberosity
      • essentially type II ossicle connected to navicular tuberosity by osseous bridge
  • Os navicular syndrome
    • Type II most commonly associated with medial foot pain
    • valgus stress injury may result in synchondrosis fracture; results in abnormal motion
References: Kalantari et al. Accessory Ossicle and Sesamoid Bones: Spectrum of Pathology and Imaging: Acessory Navicular(Os Tibiale Externum, Os Naviculare Secundarium).  Obtained via world wide web at
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Additional Details:

Case Number: 57283169Last Updated: 2011-11-08
Anatomy: Skeletal System   Pathology: Normal/Variants
Modality: Conventional Radiograph, MRAccess Level: Readable by all users
Keywords: os naviculare

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