It is pain, stiffness, or discomfort in the lower back area below the costal margin and above the gluteal creases.
Low back pain is also called spinal pain or lumbago.
Nonspecific low back pain is without identifiable specific causes and makes up 90-95% of all low back pain cases.  It also includes pain felt in the proximal lower extremities.
Patients with low back pain may have mobility deficits caused by severe or progressive neurologic disorders or comorbidities.
Specific spinal pathology includes cauda equina syndrome, tumor, infection, ankylosing spondylitis, or inflammatory disorders.
Low back pain associated with radiculopathy or spinal stenosis is dermatomal pain with or without neurologic deficits that is most often caused by nerve root compression.