A shin splint, also known as medial tibial stress syndrome, is pain along the inside edge of the shinbone (tibia) due to inflammation of tissue in the area. Generally this is between the middle of the lower leg and the ankle. The pain may be dull or sharp, and is generally brought on by high-impact exercise that overloads the tibia. It generally resolves during periods of rest. Complications may include stress fractures. Shin splints typically occur due to excessive physical activity. Groups that are commonly affected include runners, dancers, gymnasts, and military personnel. The underlying mechanism is not entirely clear. Diagnosis is generally based on the symptoms, with medical imaging done to rule out other possible causes. Shin splints are generally treated by rest followed by a gradual return to exercise over a period of weeks. Other measures such as nonsteroidal anti-inflammatory drugs (NSAIDs), cold packs, physical therapy, and compression may be used. Shoe insoles may help some people. Surgery is rarely required, but may be done if other measures are not effective. Rates of shin splints in at-risk groups range from 4% to 35%. The condition occurs more often in women. It was first described in 1958. Signs and symptoms Shin splint pain is described as a recurring dull ache, sometimes becoming an intense pain, along the inner part of the lower two-thirds of the tibia. The pain increases during exercise, and some individuals experience swelling in the pain area. In contrast, stress fracture pain is localized to the fracture site. Women are several times more likely to progress to stress fractures from shin splints. This is due in part to women having a higher incidence of diminished bone density and osteoporosis. Causes Shin splints typically occur due to excessive physical activity. Groups that are commonly affected include runners, dancers, and military personnel. Risk factors for developing shin splints include: Flat feet or rigid arches Being overweight Excessively tight calf muscles (which can cause excessive pronation) Engaging the anti-pronatory (supinating) muscles in excessive amounts of eccentric muscle activity Undertaking high-impact exercises on hard, non-compliant surfaces (such as running on asphalt or concrete) People who have previously had shin splints are more likely to have them again. Pathophysiology While the exact mechanism is unknown, shin splints can be attributed to the overloading of the lower leg due to biomechanical irregularities resulting in an increase in stress exerted on the tibia.