Accessory navicular bone

What is accessory navicular bone?

Most of the people have the same number of bones in there feet. Not infrequently some lucky person will have an extra bone which we call ‘accessory’.

One of the common accessory bones is the accessory bone which lies in the instep of the foot at the highest point of arch (see fig).

Anatomy


Where is accessory navicular located?

The navicular bone of the foot is one of the small bones on the mid-foot (Figure 1). The bone is located at the instep, the arch at the middle of the foot.

FIGURE 1

One of the larger tendons of the foot called the posterior tibial tendon attaches to the navicular before continuing under the foot and into the forefoot (Figure 2). This tendon is a


FIGURE 2

tough band of tissue that helps hold up the arch of the foot. If there is an accessory navicular, it is located in the instep where the posterior tibial tendon attaches to the real navicular bone (Figure 3).


FIGURE 3

The accessory navicular is a congenital anomaly, meaning that you are born with the extra bone. As the skeleton completely matures, the navicular and the accessory navicular never completely fuse into one solid bone. The two bones are joined by fibrous tissue or cartilage. Girls seem to be more likely to have an accessory navicular than boys.