Accessory Navicular Syndrome
What is the Accessory Navicular?
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 attaches 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.
What is Accessory Navicular Syndrome?
People who have an accessory navicular often are unaware of the condition if it causes no problems. However, some people with this extra bone develop a painful condition known as accessory navicular syndrome when the bone and/or posterior tibial tendon are aggravated. This can result from any of the following:
- Trauma, as in a foot or ankle sprain
- Chronic irritation from shoes or other footwear rubbing against the extra bone
- Excessive activity or overuse
- Many people with accessory navicular syndrome also have flat feet (fallen arches). Having a flat foot puts more strain on the posterior tibial tendon, which can produce inflammation or irritation of the accessory navicular.
The term arch pain (often referred to as arch strain) refers to an inflammation and/or burning sensation at the arch of the foot.
There are many different factors that can cause arch pain. A structural imbalance or an injury to the foot can often be the direct cause. However, most frequently the cause is a common condition called plantar fasciitis. The plantar fascia is a broad band of fibrous tissue located along the bottom surface of the foot that runs from the heel to the forefoot. Excessive stretching of the plantar fascia, usually due to over-pronation (flat feet), causes plantar fasciitis.
The inflammation caused by the plantar fascia being stretched away from the heel often leads to pain in the heel and arch areas. The pain is often extreme in the morning when an individual first gets out of bed or after a prolonged period of rest. If this condition is left untreated and strain on the longitudinal arch continues, a bony protrusion may develop, known as a heel spur. It is important to treat the condition promptly before it worsens.
What Is Flatfoot?
Flatfoot is often a complex disorder, with diverse symptoms and varying degrees of deformity and disability. There are several types of flatfoot, all of which have one characteristic in common: partial or total collapse (loss) of the arch.
Other characteristics shared by most types of flatfoot include:
- “Toe drift,” in which the toes and front part of the foot point outward
- The heel tilts toward the outside and the ankle appears to turn in A tight Achilles tendon, which causes the heel to lift off the ground earlier when walking and may make the problem worse
- Bunions and hammertoes may develop as a result of a flatfoot.
Flexible flatfoot is one of the most common types of flatfoot. It typically begins in childhood or adolescence and continues into adulthood. It usually occurs in both feet and progresses in severity throughout the adult years. As the deformity worsens, the soft tissues (tendons and ligaments) of the arch may stretch or tear and can become inflamed.
The term “flexible” means that while the foot is flat when standing (weight-bearing), the arch returns when not standing.
Symptoms, which may occur in some persons with flexible flatfoot, include:
- Pain in the heel, arch, ankle, or along the outside of the foot
- “Rolled-in” ankle (pronation)
- Pain along the shin bone (shin splint)
- General aching or fatigue in the foot or leg
Low back, hip or knee pain.