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Disease Profile

Accessory navicular bone

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Accesory navicular syndrome


Congenital and Genetic Diseases


An accessory navicular bone is an extra bone or piece of cartilage located in the middle of the foot near the navicular bone, the bone that goes across the foot near the instep. It is present from birth (congenital) and is a common trait.[1][2] The reported incidence differs among populations and ethnic groups, and they are mostly reported as incidental findings in anatomical and imaging studies, estimated to occur in approximately 2 to 20% of the general population.[3] There are three types of accessory navicular bones which are differentiated by location, size, and tissues involved (bone and/or cartilage). Although some people with an accessory navicular bone never develop symptoms, a bump can develop in the affected region that can lead to irritation, swelling, and pain. This painful condition is sometimes referred to as "accessory navicular syndrome."[4][1] Inheritance appears to be autosomal dominant.[1][2] If symptoms occur, treatment may include immobilizing the foot with a cast or removable boot; applying ice; physical therapy; and orthotic devices, such as arch support.[4][1]

 Click here to view a diagram of the foot.


While some individuals with an accessory navicular bone never experience symptoms, others can develop a painful condition, sometimes referred to as accessory navicular syndrome. This occurs when the bone and/or connective tissue are aggravated. This can be caused by injury to the affected region, chronic irritation from from shoes or other sources, and excessive activity or overuse. Symptoms of accessory navicular syndrome usually occur around adolesence and may include development of a painful, red or swollen bump on the midfoot (inner side of the foot above the arch).[4]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Abnormality of the os naviculare pedis
Autosomal dominant inheritance
Pes planus
Flat feet
Flat foot

[ more ]



An accessory navicular bone is typically considered to be a developmental abnormality present from birth (congenital). Research involving large studies of families of individuals with accessory navicular bone suggests a genetic influence with possible autosomal dominant inheritance. The exact cause of accessory navicular bone is unknown; however, it may be related to an incomplete joining (fusion) of bones and connective tissue during development and/or an abnormal separation of affected bones and connective tissue.[5][6]


If the accessory navicular bone is causing symptoms, activities may be restricted and a softer shoe may be recommended until the symptoms go away. If the symptoms persist, a specially and carefully made shoe support may be tried. For people with accessory navicular bone who experience severe symptoms, surgery may be considered to remove the bony growth. Other treatments may include medications such as nonsteroidal anti-inflammatories (NSAIDs), immobilizing the area with a cast or boot, and physical therapy.[4]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The FootHealthFacts.org Website was created and is maintained by the American College of Foot and Ankle Surgeons. Click on FootHealthFacts.org to view a resource page on Accessory Navicular Syndrome.

In-Depth Information

  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Accessory navicular bone. Click on the link to view a sample search on this topic.


  1. Victor A. McKusick. NAVICULAR BONE, ACCESSORY. OMIM. 9/16/2010; https://www.omim.org/entry/161600. Accessed 9/2/2016.
  2. Dobbs MB & Walton T. Autosomal Dominant Transmission of Accessory Navicular. The Iowa Orthopaedic Journal. 2004; 24:84-85. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1888424/.
  3. Kalbouneh H, Alajoulin O, Alsalem M, Humoud N, Shawaqfeh J, Alkhoujah M, Abu-Hassan H, Mahafza W & Badran D. Incidence and anatomical variations of accessory navicular bone in patients with foot pain: A retrospective radiographic analysis. Clin. Anat. 2017; 3:436–444. https://www.ncbi.nlm.nih.gov/pubmed/28295608.
  4. Accessory Navicular Syndrome. American College of Foot and Ankle Surgery. https://www.foothealthfacts.org/footankleinfo/Accessory_Navicular_Syndrome.aspx. Accessed 9/2/2016.
  5. Peter A Ugolini, Steven M Raikin. The accessory navicular. Foot and Ankle Clinics. March 2004; 9(1):165-180. https://www.ncbi.nlm.nih.gov/pubmed/15062220.
  6. Dobbs MB Walton T. Autosomal dominant transmission of accessory navicular. Iowa Orthop J. 2004; 24:84-85. https://www.ncbi.nlm.nih.gov/pubmed/PMC1888424.

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