What is the difference between a spinal tap and a bone marrow aspiration?

Completelt different: Spinal tap is done by putting a needle to the lumbar( lower back area) spinal canal space- to obtain cerebro spinal fluid. Bone marrow aspiration is done on the pelvic bone/hip bone - by putting a needle into the bone- going to the marrow space and aspirate the blood part inside the bone ( i.e. Marrow). The indication, procedure, technique, etc area different. Completely different procedures.