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Spinal anesthesia is done in a similar way. But the anesthetic medicine is injected using a much smaller needle, directly into the cerebrospinal fluid that surrounds the spinal cord. The area where the needle will be inserted is first numbed with a local anesthetic. Then the needle is guided into the spinal canal, and the anesthetic is injected. This is usually done without the use of a catheter. Spinal anesthesia numbs the body below and sometimes above the site of the injection. The person may not be able to move his or her legs until the anesthetic wears off.
Normal sperm densities range from 15 million to greater than 200 million sperm per milliliter of semen. You are considered to have a low sperm count if you have fewer than 15 million sperm per milliliter or less than 39 million sperm total per ejaculate.
A neuron, also known as a neurone (British spelling) and nerve cell, is an electrically excitable cell that receives, processes, and transmits information through electrical and chemical signals. These signals between neurons occur via specialized connections called synapses.