-osis. 1  1 suffix meaning a (specified) action, process, or result: homeosis, narcosis, zygosis. 2  2 suffix meaning increase in a pathological condition: calcicosis, psittacosis, varicosis. -osis. , pl. Combining form meaning a process, condition, or state, usually abnormal or diseased; production of an abnormal substance, increase of a normal substance, or parasitic infestation.
If non-surgical treatment fails to relieve the symptoms of accessory navicular syndrome, surgery may be appropriate. Surgery may involve removing the accessory bone, reshaping the area, and repairing the posterior tibial tendon to improve its function. This extra bone is not needed for normal foot function.
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.