Foot Issues

Shin Splints

Causes
Shin splints usually result from overuse. Repeated movements of the foot can cause damage where the tibialis muscles attach to the tibia. Soon the edge of the muscles may begin to pull away from the bone. The injured muscle and the bone covering (the periosteum) become inflamed.

Overuse commonly happens after changes in training. Increasing running speed and distance and running on hard or angled surfaces can contribute to overuse. Overuse can also occur from running in flimsy foot-wear or in shoes with soles that are worn out.

Anterior shin splints tend to affect people who take up a new activity, such as jogging, sprinting, or playing sports that require quick starts and stops. The unfamiliar forces place a heavy strain on the anterior tibialis muscle, causing it to become irritated and inflamed. This commonly happens when people who aren’t regular runners decide to go on a long jog. The anterior tibialis muscle must work hard to control the landing of the forefoot with each stride. Running downhill puts even more demands on this muscle in order to keep the forefoot from slapping down. People who run on the balls of their feet or who run in shoes with poor shock absorption also tend to get anterior shin splints.

Posterior shin splints are generally caused by imbalances in the leg and foot. Muscle imbalances from tight calf muscles can cause this condition. Imbalances in foot alignment, such as having flat arches (called pronation), can also cause posterior shin splints. As the foot flattens out with each step, the posterior tibialis muscle gets stretched, causing it to repeatedly tug on its attachment to the tibia. The posterior tibialis muscle attachment eventually becomes damaged, leading to pain and inflammation along the inside edge of the lower leg.

A stress fracture in the tibia is a serious problem that at first may have the same symptoms as shin splints. A stress fracture is a crack in a weakened area of bone. Continual stresses from running on hard surfaces or from heavy strain in the tibialis muscles can weaken and eventually fracture the tibia. People with shin pain who try to work through it sometimes end up developing a stress fracture in the tibia.

A concerning complication of shin splints is compartment syndrome. Compartment syndrome is a condition where pressure from muscle damage and swelling builds up inside a section, or compartment, within the body. There are four compartments in the lower limb. As the pressure builds in the compartment, the small blood vessels (called capillaries) that supply blood to the muscles in the compartment are squeezed shut. This happens when the pressure in the compartment is higher than the blood pressure that keeps the small blood vessels open. When the muscle loses its blood supply it begins to ache, like a muscle cramp.

If the pressure continues to rise, it can squeeze the larger blood vessels and nerves as well. Patients may feel coldness, numbness, and swelling in the lower leg and foot. If pressure builds up and is not treated, it can cause serious tissue damage in the leg and foot.

Symptoms
Dull, aching pain is felt where the involved tibialis muscle attaches to the tibia. Redness and swelling can also occur in this area. Tenderness is felt where the muscle attaches to the bone.

Anterior shin splints are usually felt on the front of the tibia, especially when using the anterior tibialis muscle to bend your foot upward.

Posterior shin splints produce symptoms along the inside edge of the lower leg. Small bumps may also be felt along the edge of the tibia in this area.

Symptoms of shin splints generally get worse with activity and ease with rest. Pain may be worse when you first get up after sleeping. The sore tibialis muscle shortens while you rest, and it stretches painfully when you put weight on your foot.