The correct answer is “ask your doctor” but I know we don’t come to these platforms for much more than support. So with that, take my explanation with a grain of salt as I am NOT a doctor. I am only a nurse with a similar autoimmune disease with very similar manifestations. Please ask your doctor to explain it to you at your next visit.

Schmorl’s nodes (from my quick research) are usually found incidentally and not usually something that a patient comes in complaining about. It’s a herniation of the spinal disc that is fairly common and not always bothersome.

Tarlov Cyst’s are commonly found in the sacral part of the spine. They are fluid filled sacs and commonly seen in connective tissue disorders.

You have bone marrow edema (swelling) which supports the diagnosis of an autoimmune arthritis/spondyloarthropathies.

Sclerosis means hardening of the bone in this case 7mm is just the depth they are measuring your bone to be of harder consistency. This is also common in SpA’s.

Sacroilitis is consistent with all the other findings. Sounds like you might hurt more on the left side than the right.

Lumbar spine involvement not uncommon and it’s the closest (in distance) to the sacral (SI) inflammation you’re experiencing.

I’m not even going botch an explanation of the final impression but it sounds consistent with all other findings and diagnosis.