Feet come in all shapes and sizes—and with a variety of arch structures, too. Cavus foot refers to an arch shape that is abnormally high and curved. Just as a low arch can lead to flatfoot problems and foot pain, high arches also come with their special challenges. Let’s take a look at why they occur and what you can do to lessen any complications from them.
What Causes High Arches?
Many times a neurological condition is to blame, such as cerebral palsy, polio, or stroke. If this is the case, the problem will likely get worse over time, and can lead to additional problems such as foot drop.
Sometimes, however, the foot structure is an inherited condition, which changes the outlook. The shape of your foot will probably not alter much over time, and you may not need the same treatment.
Recognizing Cavus Foot
This foot structure can be easily seen, because the arch doesn’t relax even when standing. Sometimes the top of the foot may even look high and rounded.
You may notice that your ankle seems unstable, and there may be pain along the outer ankle and the outer side of the foot. In addition, calluses may develop along the outside of the sole because of the extra pressure. They can also develop on the heel and ball of the foot, because that’s where most of your weight rests with this condition.
A common complication is that the plantar fascia under the foot that supports the arch is stretched too far during your stride, leading to damage and resulting in heel pain or inflammation of the tissue. Severe cases can also lead to stress fractures in the foot.
Other, more serious injuries that are more likely in patients with high arches include:
- Peroneal tendon issues. The peroneal tendons are located on the outside of your foot (pinky toe side) and help stabilize your ankle, as well as roll the foot outward (eversion) or flex it downward (plantar flexion). High arches forces these tendons to work harder and expose them to extra stress and friction, resulting in injury.
- Ankle sprains. People with high arches tendon to carry excess weight on the outside of the foot, rather than a more balanced distribution. This uneveness creates chronic tension in lateral ankle ligaments, which causes them to lose stability over time. Feet in this condition are more prone to rolling inward during activity, leading to a sprain.
- Fifth metatarsal fractures. The fifth metatarsal is a long, thin bone on the outside of the foot. In high-arched feet, the fifth metatarsal must endure increased levels of contact with the ground, bearing more weight that it’s normally designed to handle. Under this pressure, tiny cracks called stress fractures may form. At the same time, an overly tight peroneus brevis tendon (which attaches to the fifth metatarsal) may begin to pull off tiny fragments of bone at the insertion point.
How Nerve Damage is Diagnosed
An evaluation of your condition will likely involve a review of your medical history and a comprehensive neurological examination. Tests might include:
- Nerve function tests. Sensory testing, autonomic reflex screening, and electromyography (EMG) tests may be ordered. These examine how well and how quickly signals to the nerves are received and responded to.
- Blood tests. These can detect the presence of diabetes, vitamin deficiencies, and other factors that can be responsible for nerve damage.
- Imaging tests. These can help identify tumors, compressions, and other potential causes of neuropathy.
- Nerve biopsy. In some uncommon cases, a small portion of a nerve might be removed and examine for any abnormalities.