This can be due to either too short a first metatarsal bone or to "hypermobility of the first ray" – metatarsal bone and medial cuneiform bone behind it – both of which result in excess pressure being transmitted into the second metatarsal head. This is a common problem that can affect the joints and bones of the metatarsals. There are two small sesamoid bones under the first metatarsal head. The next most frequent site of metatarsal head pain is under the second metatarsal. Metatarsalgia, literally metatarsal pain and colloquially known as a stone bruise, is a general term used to refer to any painful foot condition affecting the metatarsal region of the foot. Metatarsalgia is most often localized to the first metatarsal head – the ball of the foot just behind the big toe.
The term describes pain and inflammation in the ball of the foot. Metatarsalgia is a common overuse injury. It is often thought of as a symptom of other conditions, rather than as a specific disease.
While track and field runners are exposed to the highest level of traumatic forces to the forefoot, many other athletes, including tennis, football, baseball, and soccer players, often have forefoot injuries. Athletes who take part in high-impact sports involving running or jumping are at high risk of forefoot injury. In the U.S., forefoot injuries, including metatarsalgia, are common in athletes who participate in high-impact sports.
People with Morton's neuroma may experience toe numbness in addition to pain in the forefoot.
Most often, the pain comes on over a period of several months, rather than suddenly. The pain is typically aggravated when walking or running. Athletes who participate in high-impact activities and may also have an inflammatory condition such as bursitis often have diffuse forefoot and midfoot pain. A condition known as Morton's neuroma (interdigital neuroma) produces symptoms of metatarsalgia due to irritation and inflammation of a nerve at the site of pain. The primary symptom of metatarsalgia is pain at the end of one or more of the metatarsal bones.
The foot can be injured during sports activities. As with many other overuse injuries, the condition may be the result of an alteration in normal biomechanics that has caused an abnormal weight distribution. Persistent stress can lead to chronic irritation and inflammation of the bone covering and adjacent tissues, such as ligaments and tendons.
The following factors can contribute to excessive localized pressure over the forefoot:
Some anatomical conditions may predispose individuals to forefoot problems. They include:
The doctor may also ask for other tests and procedures to help in the diagnosis and in determining the proper treatment. These can include traumatic disorders, circulatory conditions, arthritis, neuroarthropathies, and conditions that result in biomechanical imbalance.
Ultrasound can help identify conditions such as bursitis or Morton neuroma that can be causing pain in the metatarsal region of the foot.
The doctor may also ask for an MRI to help detect and diagnose many causes of pain in the metatarsal and midfoot regions. X-rays may be helpful in excluding other causes of forefoot pain.
A bone scan can pinpoint places of inflammation.