Marfan Syndrome: Nerves A thin layer of tissue called the Dura lines the brain and spinal cord. Although not a very common finding, in MFS the Dura may be weakened and expand. This is called 'dural ectasia', and most often arises in the lower back. As it expands it presses on nerves. This causes back pain and numbness or pain in the legs. Occasionally this problem can arise at the top of the neck and around the brain and give rise to headaches. The best way to investigate this is with MRI. If it is present it may require an operation to relief the pressure on the nerves. (Review date August 2019) If you would like the clinical references for the information used in this article, please contact us via the Information Standards Enquiry from.