The Peripheral Nervous System (PNS)
Peripheral nerves are an integral part of the human nervous system. The nervous system consists of:
- Central nervous system (brain and spinal cord)
- Peripheral nervous system
Peripheral nerves reside outside your brain and spinal cord. They relay information between your brain and the rest of your body.
The peripheral nervous system is divided into two main parts:
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Autonomic nervous system (ANS): Controls involuntary bodily functions and regulates glands.
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Somatic nervous system (SNS): Controls muscle movement and relays information from ears, eyes and skin to the central nervous system.
Nerves In the Peripheral Nervous System
- Brachial plexus (radial nerve, median nerve, ulnar nerves)
- Peroneal nerve (foot drop)
- Femoral nerve
- Lateral femoral cutaneous nerve
- Sciatic nerve
- Spinal accessory nerve
- Tibial nerve
Three types of peripheral nerves can be found within the two main areas of the peripheral nervous system:
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Sensory: Connects the brain and spinal cord to your skin and allow you to feel pain and other sensations.
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Autonomic: Controls involuntary function (e.g., blood pressure, digestion, heart rate).
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Motor: Connects the brain and spinal cord to muscles to stimulate movement.
When we move, the brain sends a message to the spinal cord. From there, the nerves carry the message to the necessary muscles to make them contract and produce movement. Similarly, when we touch an object, sensory information is carried through the nerves to the spinal cord and then to the brain so we can make sense of that information.
Symptoms of Peripheral Nerve Disorders
Peripheral nerve disorders distort or interrupt messages sent between the brain and the rest of the body. This can result in:
- Painful cramps
- Numbness
- Muscle weakness (most common symptom)
- Tingling or burning
Unlike the brain and spinal cord, peripheral nerves can regrow after an injury. However, surgery is often required to reconnect the peripheral nerves so that movement and sensation can be restored.