What is spinal stenosis and what causes it? I have it in my cervical and lumbar spine. My 15 yr old just had X-ray show it around l5s1. Causes?

Cervical stenosis. Causes: -narrowing of cervical spinal canal -associated other predisposing factors -congenital cervical fusions -ligamentous instability -intervertebral disc disease.
Narrow spinal canal. Most cases are congenital and involve a mild to moderate narrowing of the diameter of the spinal canal. In many cases, it is asymptomatic and discovered coincidentally when an MRI is done for a different reason. However, with age, and degenerative changes, the canal can narrow further and compress nerve roots and even spinal cord since your son has also, this is familial and genetic.