KESESUAIAN UKURAN KANALIS SPINALIS LUMBAL BERDASARKAN ULTRASONOSGRAFI DENGAN MR MYELOGRAFI LUMBOSACRAL PADA PENDERITA NYERI PUNGGUNG BAWAH = THE COMPATIBILITY BETWEEN THE SIZE OF LUMBAL SPINAL CANAL BASED ON ULTRASONOGRAPHY AND MR MYELOGRAPHY LUMBOSACRAL IN PATIENTS WITH LOW BACK PAIN - JUFIANTI, EMILYA (2019)