The study in normal, with the exception of two levels.
"L4-5, there is a broad-based disc herniation and mild facet arthrosis. There is a mild to moderate spinal stenosis and bilateral foraminal narrowing. Decreased disc signal is seen at this level." >>
At this level, which is low down in the lumbar spine, has a herination present. This means that the annulus fibrosis, which is the cartilage ring of the disc complex has a tear in it, which has allowed some of the nucleus pulposus to lead out or herniate. The nucleus pulposus is the jelly like center of the disc complex.
The spinal canal is a little narrowed (stenosis). The neural foramina are the holes through which the nerve roots exit the spine. There holes are also a little narrowed.
The decreased signal means that the disc appears dark or black on the MRI. This is indicative of loss of water content in the disc. Diseccation (loss of water) of the disc is one of the first signs of disc degeneration.
However, the report does NOT mention that the nerve roots are actually being touched or compressed by the above findings.
"L5-S1, there is a disc bugle asymmetric to the right. There is no spinal stenosis or foraminal narrowing. There is mild arthrosis." >>
Here there is a disc bulge, which protrudes more to the right than the left side. There is NO mention of a tear or herniation, just the bulge. The bulge is not touching anything, nor is it narrowing the canal or foramina.
There is some mild degenerative changes in the vertebra. This is usually referring to the facet joints, which are the joint in the back of the vertebra.
You really need to discuss the finding on the study with your physician. Findings do not mean much until they are correlated with your history and examination.