Although it has long been known that many people complain of pain in the lower part of the back following lumbar puncture, little significance has been attached to the origin of this complaint. Investigation of this problem has recently brought to light some of the factors apparently responsible for this disability.
Introduction of the needle beyond the neural canal has been the chief agent in producing the pathologic changes to be described. Under the topic "Failure to Obtain Fluids" Levinson1 stated: "The needle may have been introduced too far into the canal. In such cases material exuding from the intervertebral disk may clog the needle." This statement furnishes evidence that injury to the nucleus pulposus occurs, the importance of which was first emphasized by Schmorl.2 Recent experiments by Keyes and Compere3 led these observers to the conclusion that the loss of material from the nucleus pulposus results