The Difference Between Lumbar and Sacroiliac Joints

The pelvic girdle area is a complex structure composed of several bones, cartilage, ligaments, muscles, and nerves. Strong ligaments and cartilage connect the hip bones that make up the pelvic area. The lumbar spine, Ilium and the sacrum bones comprise the pelvic area. The cartilage in between the bones acts as the glue and cushion to prevent grinding and friction upon movement.

The lumbar joint

The lumbar spine makes up the lower back area. It curves inwards towards the abdomen. The lumbar spine starts about six inches below the shoulder blades. It connects the thoracic spine at the top and the sacral spine at the bottom.

The lumbar spine is composed of five vertebrae – L1 to L5. The function of the lumbar spine is to carry the majority of the upper body’s weight.

The lowest vertebra of the lumbar spine, the L5, connects to the sacral spine, S1. This joint is also known as the lumbosacral joint responsible for the hip’s swaying movement during walking and running activities.

The sacroiliac joint

The sacroiliac joint connects the iliac crests; the bone that makes up part of the hip joint, to the sacrum; the triangular bone at the bottom of the spine. This sacroiliac joint transfers the forces of the upper body to the lower body parts, to the pelvis and the legs. The sacroiliac joint is very stable and strong. There is very little motion in the joint.

The difference between the lumbar and sacroiliac joints

The lumbosacral and sacroiliac joints are located approximately near each other. The lumbar vertebra connects horizontally to the sacrum while the sacrum connects vertically to iliac bones located on both sides of the pelvic girdle.

The cartilage that holds the bones together creates the joints and absorbs pressure and body weight.

Causes of lower back pain

Many structures in the lumbar spine and sacrum can cause pain that can be felt in the lower back area. Any nerve irritation in the area, disc degeneration, muscles, and bone anomalies can all cause pain in the lower back area.

Most lumbar spine disorders are interrelated. For example, instability in the joints can lead to disc deterioration which will result in nerve pressure and will cause painful sensation around the pelvic area.

Pain in the sacroiliac joint will sometimes resemble sciatic pain. The pain may be felt in the lower back, hip and may radiate to the groin area or down to the back of the legs. It is more common in middle-aged women, especially during pregnancy.

Diagnosing lumbar and sacroiliac dysfunctions

There is no single test that can diagnose lumbosacral and sacroiliac joint dysfunction. It needs multiple diagnostic tools to come up with an accurate analysis of the dysfunction. The pain that lumbar and sacroiliac dysfunction is similar to many lower back pain causes.

The diagnostic process will start with the chiropractic physician asking and reviewing your medical history. Medical history includes your usual activities, injuries that may contribute to the symptoms, habits, sleep patterns, diet and exercise. Then he/she will perform a physical examination and will ask about the pain and other symptoms. The chiropractor will discuss the best treatment choices for you.

Sources:

https://www.spine-health.com/conditions/spine-anatomy/lumbar-spine-anatomy-and-pain

https://www.spine-health.com/conditions/spine-anatomy/sacroiliac-joint-anatomy

https://www.spine-health.com/conditions/sacroiliac-joint-dysfunction/accurate-diagnosis-sacroiliac-joint-dysfunction