How does spinal decompress. traction change disc morphology on a rounded, degenerated, bulging disc axial view ? does disc "heighten" and contract inwards or does it absorb fluid and expand outwards?

Depends on timing: Traction to treat disc degeneration has limited evidence, although as disc bulging tends to occur from axial compression, traction tends to draw in the bulge.

Spinal decompression: Remember, any changes that occur with traction are temporary. Once normal weight bearing is restored, all changes revert to pre-traction state. Inversion tables do exactly the same thing for about $250 total vs. Around $200 per treatment with traction. Upright MRI scans show that the disk will compress and shorten with upright load, and heighten with disc contracting inwards without loading.