According to "The New York Times" Health Guide, leg pain, including lateral leg pain, or pain on the side of the upper and lower leg that faces away from the body, may be caused by repetitive strain, nerve injuries, blood vessel disorders, direct trauma and certain medical conditions. Lateral leg pain is especially common among athletes such as runners, and can range from mild to severe.
Lateral Collateral Ligament Sprain
According to Cedars-Sinai Medical Center, or CSMC, the lateral collateral ligament, or LCL, is a thin band of tissue located on the outside aspect of the knee. The LCL joins the femur, or thigh bone, to the fibula, the smaller of the two long bones in the lower leg. Along with the other knee ligaments, the LCL helps stabilize the knee as it moves through its full range of motion. Possible symptoms associated with an LCL sprain include the sensation of knee instability, pain on the outside aspect of the knee and leg, joint locking or catching, foot numbness or weakness, and stiffness, swelling and tenderness in the affected area. The CSMC states that LCL sprains are graded from 1 to 3 based on the severity of the sprain; a grade 3 sprain is more severe than a grade 1 sprain.
IT Band Syndrome
Iliotibial, or IT, band syndrome can cause pain in the lateral portion of the leg. The IT band is a thick, fibrous connective tissue sheath that runs from the iliac crest to the lateral knee. The Sports Injury Clinic website states that IT band syndrome, also known as iliotibial band friction syndrome, or ITBFS, is a condition in which the IT band rubs against the lateral epicondyle of the thigh bone, on the outside aspect of the knee. Over time and with repetitive movement, the IT band can generate friction and pain in the affected area. IT band syndrome is a common injury among runners. Along with pain in and around the femur's lateral epicondyle, common signs associated with IT band syndrome include IT band tightness, pain in the involved area that's made worse by running, pain with knee bending or straightening, a decreased ability to lift the thigh away from the body and trigger points in the gluteal muscles.
Common Peroneal Nerve Dysfunction
According to the University of Maryland Medical Center, common peroneal nerve dysfunction involves damage of the peroneal nerve, which is located on the lateral aspect of the lower leg, near the upper end of the fibula bone. The peroneal nerve is a branch of the sciatic nerve. Common peroneal nerve dysfunction is a type of peripheral neuropathy, as it involves damage to a nerve that resides outside the brain or spinal cord. Possible causes of this condition include direct trauma to the knee, fracture of the fibula and surgical complications. Common signs and symptoms associated with common peroneal nerve dysfunction include pain, numbness or tingling in the outer part of the upper or lower leg and the top of the foot, ankle or foot weakness, foot drop -- the inability to hold the foot horizontal -- and walking difficulties.
