What is the normal range of spinal tap opening pressure?

Normal range is variable based upon supine versus sitting up, diurnal variations, etc., but the most important thing is what is considered "Low" and "High".

For any patient, despite of age and BMI, supine opening pressure above 250 mm of water is considered high, and <6 mm of water is considered low...

Although 250 mm is considered the upper limit of normal, this is often dependent on the body habitus and position of the patient. In someone with a BMI >40, OP may be up to 265 mm and come down somewhat when the legs are extended. Unfortunately, this variability is challenging because these are the ...

I agree with the above ratings. However, I also like to highlight those that have the usual symptoms and signs including intractable headache, +/- papilledema, and experience immediate relief of their headaches post-LP. However, the headaches will build up back to where they were pre-LP a few days l...