We received a question regarding spondylolisthesis. Spondylolisthesis is a slippage of one vertebrae over another. Most commonly this refers to slippage in the lumbar (lower) part of the back. Slippage of the vertebrae in the neck is usually called cervical subluxation (and when it is the first vertebrae slipping on the second it is called atlanto-axial instability – the first vertebrae in the neck is the atlas and the second is the axis). Less commonly this occurs in the thoracic vertebrae (the back bones attached to the ribs).
In our experience, in the neck, the big concern is usually the pinching of the spinal cord causing neurological symptoms.
Pain may also be a symptom. We have tended to see pain less commonly in the neck than the neurological symptoms.
In the lumbar region of the back, we tend to see the neurological symptoms less commonly and pain more commonly. Weakness of the arms would not be associated with spondylolisthesis of the lumbar spine.
Ligament laxity is more common in people with Down syndrome and can cause a variety of orthopedic problems including spondylolisthesis and cervical subluxation.
I encourage you to read the chapter on Orthopedic Problems in our book The Guide to Good Health for Teens & Adults with Down Syndrome - https://www.woodbinehouse.com/product/guide-good-health-teens-adults-syndrome/.