If you have posterior tibial #tendonitis you'll feel pain on the inner side of your foot. With this condition most pain is felt during the "push off" motion done with walking. #posteriortibialtendonitis
The accessory navicular (os navicularum or os tibiale externum) is an extra bone or piece of cartilage located on the inner side of the foot just above the arch. It is incorporated within the posterior tibial tendon, which has its insertion to the bone in this area. An accessory navicular is congenital (present at birth). It is not part of normal bone structure and therefore is not present in most people.