The lumbar manometric test is a routine procedure whenever disease of the spinal cord is suspected. Stookey, Merwarth and Frantz1 and Stookey and Klenke2 have standardized the original test of Queckenstedt by introducing new procedures in it, greatly increasing its value. Their contributions consisted in adding touch compression of the jugular veins, timing and charting the rise and fall of pressure after firm jugular compression, and finally in emphasizing the value of Ayala's index, or what they called the pressure index.
Attention to a host of details which modify the pressure readings is still required, and the chief source of error is concerned with the maneuvers incident to manual jugular compression. Elsberg and Hare3 introduced the amyl nitrite test for spinal subarachnoid block, because of the disadvantages of manual jugular compression. The amount of pressure on the jugular veins that is often necessary may cause the patient
GRANT WT, CONE WV. GRADUATED JUGULAR COMPRESSION IN THE LUMBAR MANOMETRIC TEST FOR SPINAL SUBARACHNOID BLOCK. Arch NeurPsych. 1934;32(6):1194-1201. doi:10.1001/archneurpsyc.1934.02250120071007