The Sacrum - Your foundation
An old sacrum/coccyx injury can cause lower back pain because the sacrum and coccyx are essential parts of the spine that help to support the upper body and protect the spinal cord. Damage to these bones can cause inflammation, muscle spasms, and nerve compression, leading to pain.
In addition, sacral instability can cause lower back pain because it can affect the alignment and stability of the spine, leading to abnormal wear and tear on the joints, discs, and ligaments. And this can cause inflammation, muscle spasms, and nerve compression, leading to pain.
Additionally, sacral instability may lead to other issues, such as muscle weakness and poor posture, further exacerbating the pain.
Essentially, your sacrum is your foundation. Old trauma to this area significantly impacts its stability and, through a chain reaction, affects structures above and below the sacrum.