The lumbar spine and the sacrum can be significant sources of dysfunction. Studies have estimated that up to 70% of adults have experienced low-back pain during their lifetime, with 50% reporting it every year (Jackson and Browning, 2005). Compared to pain in the cervical spine, low-back pain more often originates from chronic behavior than from acute trauma. "Back pain has been identified as the leading cause of disability among persons under the age of 45 years and the third leading cause of disability among those 45 years of age or older" (McGeary et al., 2003). Back pain accounts for 200,000 office visits per year—1.8% of the total medical visits in the United States (Jackson and Browning, 2005). Despite its high percentage of occurrence, only 25% of people with physical symptoms seek medical attention. Most back injuries are relatively minor and will resolve within a month; however, a minority of people—around 10%—develop chronic conditions that make up 80% of the cost associated with the disorder.

Management of low-back pain continues to be challenging (Maluf et al., 2000), especially because there are many different variables and sources from which the pain can originate. Despite having knowledge of the structures involved, a large percentage (up to 85%) of cases are classified as "nonspecific" because a definitive diagnosis cannot be made with current methods (O’Sullivan, 2005). A nonspecific diagnosis is sometimes referred to as "lumbago," but the cause of pain is usually narrowed down through a process of elimination to ensure that the correct treatment is administered.

This chapter seeks to clarify some of the major causes of lumbar spine and sacral dysfunction. In addition to reviewing the structures, this chapter discusses:

• Specific bony landmarks for palpation

• Soft tissue structures, including the muscles of the region

• The movements of the region, and basic biomechanics of the lumbar spine and sacrum

• Manual muscle tests for the lumbar spine

• Dermatome and trigger-point referral patterns for the involved muscles

• Some common causes of dysfunction and how to assess and treat them using soft tissue therapy