Spinal nerve nerve roots result in typical patterns of neurologic defects (muscle weakness, abnormal sensation, changes in reflexes) that allow localization of the responsible lesion. There are several procedures used in sacral nerve stimulation for the treatment of various related disorders. Sciatica is generally caused by the compression of lumbar nerves L4, or L5 or sacral nerves S1, S2, or S3, or by compression of the sciatic nerve itself. Spinal nerve A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal
Timeline of longest spaceflights Timeline of longest spaceflights Timeline of longest spaceflights is a chronology of the longest spaceflights. Many of the first flights set records measured in hours and days, the space station missions of the 1970s and 1980s pushed this to weeks and months, and by the 1990s the record was pushed to over a year and has remained there into the 21st century. A modern long-duration mission is the ISS year long mission (2015–2016) aboard the International Space Station. The most significant issue in such missions is the effects of spaceflight on the human body, due to such factors as zero-g