The causes of backache often elude diagnosis, while leg pain may be somewhat easier to trace. The Cleveland Clinic reports that 80 percent of back pain cases never receive confirmation of a specific cause. Painful conditions of the back and legs, however, generally fall into three categories: conditions that existed from birth, conditions caused by injury and conditions caused by musculoskeletal degeneration. Even a broad diagnosis in one of these groups can help patients manage or resolve leg and back pain.
Scoliosis
Uneven leg lengths or an abnormal lateral twist in the spine can generate chronic back or leg pain over time, as the American Chiropractic Association reports. Patients who are born with or develop scoliosis, an extreme or atypical spinal curvature, may experience both of these stressful conditions at once.
Legs of different lengths throw the hips and spine out of alignment and place extra strain on the back and legs. Recurrent backache, knee pain or hip pain may result.
Muscle Strain
Acute or chronic injury to the upper and lower body can occur in sports and occupations that involve strenuous use of the back and legs. The Mayo Clinic reports that jobs as disparate as nursing, construction work and computer tasks can all cause such muscle strain over time. Heavy lifting, repetitive motions and awkward working postures produce the type of stress that can cause muscle fibers to weaken and tear. Sports that require bursts of speed or excessive use of the leg or back muscles, such as football, baseball, tennis and running, may lead to isolated or recurrent cases of backache and leg pain.
Osteoarthritis
Bone, joint and vertebra deterioration can shift the skeletal balance and affect how people carry themselves. Osteoarthritis can change spinal alignment so gradually that patients don't notice until leg or back pain arises. The University of Maryland Medical Center relates that a decrease in muscle tone and intentional shifts in posture occur simultaneously with the development of bone spurs. The knees, ankles and vertebrae may all experience arthritis degeneration, defined by periodic or continual pain in the back and legs.
Sciatica
Sciatica may begin as back pain during changes to the spine brought on by vertebral or disk deterioration. When patients' spinal alignment changes sufficiently to put pressure on the adjacent sciatic nerve, leg pain will result. UMMC reports that sciatica pain usually locates on one side of the body, expressed as an ache, sharp pain or tingling that radiates somewhere between the back and foot.
