Cause

In each foot there are five metatarsal bones that run from the arch to the toe joints. The first metatarsal is shorter and thicker than the other four bones, which are usually similar in size. During the push-off phase of walking, jumping or running, body weight is transferred to the toes and metatarsals. The first and second metatarsal bones take the brunt of this force, which can be as much as 275 percent of body weight.

Most metatarsal problems develop when the impact load or the mechanics of the foot affect the way weight is distributed. This can put excess pressure on the metatarsals, leading to inflammation and pain, especially in the metatarsal heads the rounded ends of the bones that connect with the toe bones.

Anything which puts extra stress on the front of the foot can cause metatarsalgia. Common examples are:

• Being overweight.
• High-heeled shoes.
• Certain foot shapes such as high-arched “cavus” foot in which the bones in the front of the foot (metatarsals) point into the sole to an excessive extent, or a long metatarsal bone which takes extra pressure.
• Claw or hammer toes which press the metatarsals down towards the ground.
• a stiff ankle which cannot be drawn up to right angles with the leg but points the foot down to the ground.
• A bunion or arthritis in the big toe can weaken the big toe and throw extra stress onto the ball of the foot. This can also happen after an operation on the big toe, such as a bunion correction.
• A stretched or irritated nerve in the ball of the foot (interdigital neuroma) or behind the ankle (tarsal tunnel syndrome) can produce pain in the ball of the foot. Diabetes can also produce irritation of the small nerves in the foot leading to a burning pain.
• Athletes or walkers occasionally get stress fractures of the metatarsal bones.
• Arthritis, gout or inflammation of the joints in the ball of the foot (metatarso-phalangeal joints) can produce local pain.