Question: What is (are) Accessory navicular bone ?
Answer: An accessory navicular bone is a small bone located in the middle of the foot. It is near the navicular bone, the bone that goes across the foot near the instep. It is a common trait, estimated to be in approximately 2 to 12% of the general population and up to 14% of children. This bone may develop a bump that can cause irritation, swelling, and pain. Click here to view a diagram of the foot.
Source: GARD

Question: What are the symptoms of Accessory navicular bone ?
Answer: What are the signs and symptoms of Accessory navicular bone? Accessory navicular bone may cause no symptoms, but in some cases causes pain, tenderness, or irritation on or around the top of the instep. It may also cause the foot to be abnormally positioned, and may limit the normal motion of the foot. Symptoms may worsen with increased activity or tight shoes. The Human Phenotype Ontology provides the following list of signs and symptoms for Accessory navicular bone. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of the skeletal system - Autosomal dominant inheritance - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Accessory navicular bone ?
Answer: What causes of accessory navicular bone? The cause of accessory navicular bone is unknown. In some cases, the condition may be related to the development of flatfoot also known as pes planus, in other cases it may be related to repeated foot and ankle sprains.
Source: GARD

Question: What are the treatments for Accessory navicular bone ?
Answer: How might accessory navicular bone be treated? 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. In children the condition usually resolves once the child stops growing. For people with accessory navicular bone who experience severe symptoms surgery may be considered to remove the bony growth. Other treatments may include non-steroidal anti-inflammatories (NSAIDs) such as ibuprofen, placing a doughnut-shaped piece of moleskin around the affected area to relieve pain and tenderness, or immobilizing the area with a cast for six weeks.
Source: GARD