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
Effect of spaceflight on the human body changes included a flattening of the eyeball and changes to the retina. Space traveler's eye-sight can become blurry after too much time in space. Another effect is known as Cosmic ray visual phenomena Because weightlessness increases the amount of fluid in the upper part of the body, astronauts experience increased intracranial pressure. This appears to increase pressure on the backs of the eyeballs, affecting their shape and slightly crushing the optic nerve. This effect was noticed in 2012 in a study using MRI scans of astronauts who had returned to Earth following at least one month in space. Such eyesight