Os Naviculare
Description
Nomenclature
- Os Naviculare
- Accessory Navicular
- Os Tibiale Externum
History
- First variant described by Swiss physician Gaspard Bahuin in 1605
- Second variant described by German anatomist Hubert von Luschka in 1858
- Third variant and classification system described by American orthopedic surgeon Emil Geist in 1914
- One of the accessory bones of the foot and ankle
Introduction
- Large accessory ossicle located medially to the navicular
- Tibialis posterior often inserts with a broad attachment
Gross Anatomy
- Located posterior to the posteromedial tuberosity of the navicular
Classification
- Type I
- Seen 30% of the time
- Oval or round sesamoid located within the distal posterior tibial tendon
- May be separated up to 5 mm from the navicular tuberosity
- Type II
- Most common variant at 50%
- Known as the os naviculare
- Triangular or heart-shaped unfused accessory ossification center
- Separated from the tuberosity by a 1–2 mm wide synchondrosis
- Type III
- Seen in 20% of cases
- Prominent tuberosity
- Thought to be a fused type II accessory navicular bone
Epidemiology
- Second most common accessory bone of the foot[5]
- Reported prevalence of 2% to 21%[6]
- Up to 45% in Asian populations[7]
- Bilateral in 50% to 70% of cases
- More common in female patients
Imaging
- Best seen on the AP or oblique radiographs of the foot
- When symptomatic, may appear as "hot spot" on bone scan
- On MRI, bone marrow edema can be seen
Pathology
- Type II is the most commonly symptomatic[8]
Clinical Significance
See Also
References
- ↑ Image courtesy of rehabymypatient.com
- ↑ Image courtesy of https://footeducation.com/
- ↑ Stolarz, Kacper, et al. "The prevalence and anatomy of accessory navicular bone: a meta-analysis." Surgical and Radiologic Anatomy 46.10 (2024): 1731-1743.
- ↑ Osiowski, Aleksander, et al. "The prevalence and clinical considerations of Os Vesalianum Pedis: A meta-analysis." Foot and Ankle Surgery (2025).
- ↑ Lawson, Jack P. "International Skeletal Society Lecture in honor of Howard D. Dorfman. Clinically significant radiologic anatomic variants of the skeleton." AJR. American journal of roentgenology 163.2 (1994): 249-255.
- ↑ Stoller, D. W. Magnetic resonance imaging in orthopaedics and sports medicine. Lippincott Williams & Wilkins, 2007.
- ↑ Ng W, Tan T, Kam J, Mehta K. The Incidence and Anatomic Variation of Os Naviculare in a Multiethinic Asian Population. J Foot Ankle Surg. 2022;61(3):456-8. doi:10.1053/j.jfas.2021.05.013
- ↑ Miller, Theodore T. "Painful accessory bones of the foot." Seminars in musculoskeletal radiology. Vol. 6. No. 02. Copyright© 2002 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.:+ 1 (212) 584-4662, 2002.