The lower back is made up of five vertebral bones, intervertebral discs, nerves, muscles, ligaments, and blood vessels in the lower back. The lumbar spine is solid and resilient, but it is also vulnerable to high-stress levels and loads, which can lead to pain and a restricted range of motion.
The total amount of lumbar motion from a neutral lordotic position is reported to be as follows:
Forward flexion: 40˚ to 60˚
Extension: 20° to 35˚
Lateral flexion: 20˚ to 30° to each side
Rotation: 10˚ to 35° to each side
What affects the range of motion of the lumbar spine and why is it important?
The lumbar spine supports the upper body and transmits the weight of the upper body to the pelvis and lower limbs. The lumbar vertebral column provides a semi-rigid axis for the body, one that enables an upright stance, and which provides attachment points for muscles to move the limbs. It also protects the spinal cord within the bony vertebral foramina. Additionally, the lower back is the primary facilitator for movements of the trunk in various directions, including front and back, side to side, and twisting motions. The lumbar vertebral column can flex and twist mainly in the last two vertebral levels. This is due to the flexible intervertebral discs present between the vertebrae.
The bony architecture of the facet joints and the ligaments present in the lumbar reason mainly limit the excessive range of motion. The 3 major spinal ligaments are the (1) anterior longitudinal ligament, (2) posterior longitudinal ligament, and (3) ligamentum flavum. Spinal tendons attach muscles to the lumbar vertebrae and also work to limit excessive movement.
How do you measure the lumbar range of motion?
Lumbar range of motion can be measured by anatomical movements such as forward flexion, lateral flexion, extension, and rotation. The range of motion of the lumbar spine is usually measured using a goniometer. You can measure the range of motion of the lumbar spine using Check My ROM, a free online tool that measures the range of motion using images.
Lumbar Spine Flexion is the movement of the lower back forward and down as if you were trying to touch your palms to the floor.
Lumbar Spine Lateral Flexion is the movement of the lower back to the side as if you were trying to touch your fingertips to the outer border of your foot.
Lumbar Spine Extension is the movement of the lower back backward and up as if you were bending behind and looking up at the ceiling.
Lumbar Spine Rotation is the movement of the lower back to the side as if you were turning your lower back to the right or left
What causes a limited lumbar range of motion?
Lifestyle
A sedentary lifestyle, or one which involves frequently prolonged sitting whether at work or school significantly increases the incidence of recurring low back pain.
Work
Jobs that involve prolonged periods of standing or walking such as teaching, dentistry, security guards, and policemen are prone to have chronic low back pain. An increased risk of a new episode of low back pain is also common in those whose jobs involve lifting/pulling/pushing objects of at least 25 lbs, such as carpentry, factory workers, welders, etc.
Age
Bony changes occur in the vertebrae as well as spinal discs which leads to a reduction of the natural lumbar curvature. This leads to a reduction in the extension as well as flexion ranges. Age also delays the healing process in the body and thus sudden lifting of heavy groceries, overdoing sporting activities without proper warm-ups, etc may result in pulled muscles causing more frequent episodes of low back pain.
The physiological causes affecting the lumbar range of motion are:
- The flexibility of the intervertebral discs.
- The shape and angulation of the facet joints of the vertebrae.
- The laxity of the ligaments and joint capsules all contribute to the lumbar spine’s range of motion.
- The range available decreases with age as degeneration occurs in the lumbar spine and surrounding soft tissues.
The pathological causes affecting the lumbar range of motion are:
- Pain (due to soft tissue trauma or a fracture)
- Muscle dysfunction (due to a mobility impairment in the hip flexor muscles- iliopsoas, tensor fasciae latae, rectus femoris, upper abdominal muscles- upper segments of the rectus abdominis and obliques, internal intercostal, hip extensor, and lower lumbar extensor muscles and related the surrounding fascia)
- Muscle stiffness and spasm (could happen due to a poor posture caused by impaired muscle performance due to stretched and weak lower abdominal muscles- lower segments of the rectus abdominis and obliques, extensor muscles of the lower thoracic region, and hip flexor muscles. Lack of the normal physiological lumbar curve, which reduces the shock-absorbing effect of the lumbar region and predisposes the person to injury)
- Ligament stress (Stress to the anterior longitudinal ligament, iliofemoral ligaments, and the posterior longitudinal ligament of the upper lumbar and thoracic spine)
- Intervertebral disc prolapse as shown in the figure below (due to trauma or age-related changes, the disc can impinge on the nerves around it causing pain)
- Spinal canal stenosis (as the spinal cord travels very close to the lumbar spine, narrowing in the lower lumbar spine that may compress the blood vessels, and nerve roots, especially with arthritic conditions causing pain)
- Spondylolysis (arthritic changes in the spine)
- Spondylolisthesis. Shown in the figure below (one vertebra when slips forward or backward relative to the adjacent vertebra may cause pain)
- Spondylolisthesis is when one vertebra when slips forward or backward relative to the adjacent vertebra Taken from: Levangie, P. K., Norkin, C. C., & Lewek, M. D. (2019). Joint structure & function: a comprehensive analysis (Sixth edition. ed.). F.A. Davis Company.
- Referred pain (from visceral organs like kidneys)
- Spinal deformities (like scoliosis which is a condition in which the spine twists and curves to one side)
- Spinal tumors
How to increase the range of motion in the lower back?
Various physical exercises can help increase the range of the cervical spine. (All images are taken from Kisner Carolyn and Lynn Allen Colby. 2012. Therapeutic Exercise: Foundations and Techniques. 6th ed. Philadelphia: F.A. Davis.)
Lumbar extension exercise
Lumbar extensor stretching in supine (Erector spinae muscle stretch)
Lumbar extensor stretching in sitting
Pelvic tilts
Lateral flexion stretch
Rotations with a theraband
Pelvic bridging
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