The lumbar fascia is one of several human connective tissue systems that are known collectively as anatomic fascia. Located in the lower region of the back, it is the outermost layer of dense soft tissue, just below the epidermis, stretching horizontally along the natural posterior waste line. As the name implies, this structure is included in the numerous muscle and bone groups that make up the area of the back known as the lumbar region. Made up of interwoven sheets of fibrous tissue, the it serves as a base of attachment for various superficial muscles and provides support for deep muscles. Elasticity in the fascia also provides shock absorption when walking, thus providing a smooth, somewhat bouncing gait.
Numerous muscles, vertebrae, and other complimentary components work together, much like a complex system of pulleys. Muscles contract and expand to turn, rotate, and tilt skeletal components both to facilitate movement and to maintain balance and ensure proper posture. Often a simple movement, such as raising an arm, requires the interaction of numerous muscles, connective tissues, bones, and joints from seemingly unrelated areas of the back and neck. For example, connective tissues like the lumbar fascia, although located in the lower back, often facilitate body movements elsewhere, such as the abdomen or shoulders.
The fascia of the lumbar region rests below the latissimus dorsi and above each gluteus maximus muscle. The lumbar fascia resembles a fan-shaped structure. Centered on the small of the spine, the narrow end of the fan shape sits in line with the waist. At the top of the lumbar fascia fan, the latissimus dorsi is directly attached and extends across most of the lower half of the back into the humerus or shoulder blade. With support from the lumbar fascia, the latissimus dorsi enables various shoulder movements, fulfilling its purpose as a member of a class of muscles known as extensors.
While supporting upper body movements, the lumbar fascia also helps support the outermost layer of abdominal muscles, known as the external abdominal obliques. These muscles begin in the lower back on either side of the spine, with ends attached just behind the narrow base of the lumbar fascia's fan shape. Continuing from the base of the fan around to the lower abdomen, the external abdominal obliques protect internal organs, support other abdominal muscles, and help compress the abdomen.
Supporting other muscles by maintaining each muscle's position and providing a framework for the attachment of superficial muscles are only two functions of the lumbar fascia. Owing to its fibrous structure, the tissues of the fascia have elastic properties. Combined with its relative proximity to the gluteus maximus muscles and various abdominal muscles, these elastic properties provide shock absorbing benefits when walking. Accordingly, an individual's gait gains a modest bounce and smoother stride.