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
Nerve supply to the skin the most densely innervated parts of the body. Though there is no specific categorization, both “free” nerve endings and unencapsulated nerve endings of myelinated axons are found within the dermis of those areas. The cornea, one of the other exposed mucous membranes, contains “free” nerve endings served by nonmyelinated axons. The conjunctiva contains a less dense distribution of “free” nerve endings that are served by both myelinated and unmyelinated axons. The distribution of the sensory neurons within the skin accounts for the large and overlapping receptive fields of the skin. The size of the receptive fields in turn explains why