@jenniferhunter I have not had an MRI of the lumbar spine, since I was told that an issue with the lumbar spine would not explain the symptoms in my arms. The MRIs of my cervical and thoracic spine were normal (or so I was told). Any sustained pressure can cause my symptoms. For example, resting my head on my arm when in bed; or sitting on the toilet; or crossing my legs; or resting my elbow on a table. For the most part, it is things that would cause numbness in normal people IF the amount time spent in those positions was MUCH longer.