Your somatic nervous system is a subdivision of your peripheral nervous system, which is all of your nervous system except your brain and spinal cord. Your somatic nervous system allows you to move and control muscles throughout your body. It also feeds information from four of your senses — smell, sound, taste and touch — into your brain.
Your somatic nervous system is a subdivision of your peripheral nervous system that stretches throughout nearly every part of your body. The nerves in this system deliver information from your senses to your brain. They also carry commands from your brain to your muscles so you can move around.
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Your somatic nervous system involves things you can consciously sense and do. Your autonomic nervous system works without you thinking about it, running the behind-the-scenes processes that keep you alive. Both are subdivisions of the peripheral nervous system, a subsystem of your overall nervous system.
Your somatic nervous system has two main jobs:
For most of your internal organs, your somatic nervous system only helps indicate organ pain using “referred pain.” This is when you feel pain in a specific area, but the pain is actually coming from a problem nearby. One of the best-known examples of this is pain from a heart attack that you feel in your left arm, back, jaw or abdomen.
One of the expert theories about why that happens has to do with your nervous system’s layout.
Another example of how your somatic nervous system can affect internal organs is controlling your breathing. Under most circumstances, you breathe automatically and without thinking about it. But you can also breathe manually, deliberately controlling when you inhale and exhale.
Your somatic nervous system spreads outward from your brain and spinal cord. In your head and neck, it does that through your cranial nerves. These are 12 pairs of nerves (which use Roman numerals to set them apart), 11 of which have connections that are part of your somatic nervous system. Cranial nerve (CN) II, which connects to your eyes, is technically part of your brain, not your somatic nervous system.
Farther down, your somatic nervous system has connections in all 31 spinal nerves. The spinal nerves branch out further and become the nerves that spread out through your body. Some of the nerves in this system are sensory. They conduct information one way: Up to your brain. Others are motor, and they also conduct information one way: From your brain to your muscles.
Both your spinal and cranial nerves continue to branch outward as smaller nerves throughout your body. They usually end at nerve endings in places like the tips of your fingers and toes, or just underneath the surface of your skin.
Your nervous system looks much like an upside-down tree, with your brain as the root of the tree and your spinal cord as the tree’s trunk. Your peripheral nervous system — especially your somatic nervous system — spreads out through the rest of your body. Because your somatic nerves end up underneath your skin’s surface or in your hands and feet, they’re like the farthest reaches of the tree’s limbs, branches and twigs.
Your peripheral nervous system consists of various types of nerve cells and structures. The cell types are as follows, with more about them listed below:
Neurons are very specialized cells that only happen in your nervous system. There, they send and relay signals throughout your body. These signals, which come in electrical and chemical forms, are how systems in your body communicate with each other. Each neuron consists of the following:
Neurons form web-like networks that are incredibly complex, with one neuron sometimes connecting to thousands of others. Neurons also come in different lengths, and some are longer or shorter, depending on location and what they do.
Glial (pronounced “glee-uhl”) cells have many different purposes, helping develop and maintain neurons when you’re young and managing how the neurons work throughout your entire life. They also protect your nervous system from infections, control the chemical balance in your nervous system and create the myelin coating on the neurons’ axons. Your nervous system has 10 times more glial cells than neurons.
Your somatic nervous system is a division of your peripheral nervous system. Your peripheral nervous system is all of the nervous tissue in your body that’s not part of your brain or spinal cord.
Because your somatic nervous system is part of your peripheral nervous system, it’s prone to conditions that cause peripheral neuropathy. This term means disease or damage to your peripheral nervous system, and some of the most common conditions and disorders that cause it include:
The symptoms of somatic nervous system problems depend on the types of nerves affected.
Damage to motor nerves affects your muscles by causing:
Damage to sensory nerves causes the following symptoms:
Many tests can help diagnose problems affecting your somatic nervous system. The most common starting point is a neurological exam, where your healthcare provider has you use different parts of your body, especially arms, hands, legs and feet, in certain ways. This can help them narrow down the source of a problem to certain nerves, areas of your spine or parts of your brain.
Other common tests include:
The treatments for issues in your somatic nervous system strongly depend on the underlying cause, related conditions or the symptoms you have. In many cases, treating the underlying cause of peripheral nervous system problems can relieve the effects on that system.
Potential treatments can include:
Many of the conditions that affect your somatic nervous system are avoidable or preventable. While it’s impossible to prevent some conditions, it’s often possible to delay their effects or limit how severe they are. The ways you can avoid, prevent or delay issues include:
A note from Cleveland Clinic
Your somatic nervous system is a system in your body that you use but don’t think about often. This part of your nervous system is how you receive information about the world around you, from the temperature outside to the smell of a favorite meal. Taking care of your somatic nervous system can make a big difference in your overall quality of life, so it’s important to prevent conditions that affect it or manage them as best you can.
Last reviewed by a Cleveland Clinic medical professional on 06/15/2022.
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