The phrenic nerve plays a key role in breathing or respiration. It causes your diaphragm to contract and expand, giving your lungs ability to inhale and exhale air. Nerve damage can cause a paralyzed diaphragm. You may feel short of breath and have problems sleeping. An irritated phrenic nerve can cause persistent hiccups.
The phrenic nerve controls your diaphragm (the large dome-shaped muscle between your abdominal and chest cavities). It’s essential to breathing. Your nerve sends signals that cause your diaphragm to contract (become thicker and flatter). This movement gives your lungs room to expand and take in air (inhalation). After this, decreased firing of your phrenic nerve relaxes your diaphragm, and your lungs recoil, pushing out air (exhalation) and becoming smaller.
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Your phrenic nerve plays a critical role in your respiratory system to aid breathing. It’s the only nerve in your nervous system that provides motor (movement) function to your diaphragm. It sends signals that cause your diaphragm to expand and contract. These movements allow your lungs to inhale and exhale air.
Your phrenic nerve also provides touch and pain sensory information to your:
Your phrenic nerve connects to the C3 to C5 cervical (neck) nerve roots of your spinal cord. The nerve:
You have a left and right phrenic nerve. Each performs the same function. The left phrenic nerve sends signals to the left part of your diaphragm, while the right phrenic nerve controls your right side.
Damage to a phrenic nerve can lead to diaphragm weakness or paralysis. A paralyzed diaphragm affects your lungs’ ability to exchange air.
Depending on the location of phrenic nerve damage, paralysis may affect one side of your diaphragm (unilateral) or both sides (bilateral). People with severe bilateral diaphragm paralysis need mechanical ventilation to breathe.
Causes of diaphragm paralysis include:
A person with unilateral diaphragm paralysis may not have significant symptoms (with some causes like neuralgic amyotrophy, there may be shoulder pain and arm weakness on their affected side). Signs of a bilateral paralyzed diaphragm include:
Sometimes, an irritated phrenic nerve causes persistent hiccups that last for days or even a month or longer. Surgical procedures, tumors and other issues may irritate your phrenic nerve, bringing on persistent hiccups.
Persistent hiccups can be uncomfortable and annoying. They can affect your ability to talk, sleep and eat. Treatments for persistent hiccups include:
These steps can keep your nervous system healthy:
You should call your healthcare provider if you experience:
A note from Cleveland Clinic
Your phrenic nerves are critical to breathing. They cause your diaphragm to become smaller or larger so your lungs can inhale and exhale air. Damage to a phrenic nerve can lead to a paralyzed diaphragm. You may experience shortness of breath and sleep problems. People who have severe damage to their phrenic nerve may need a mechanical ventilator to breathe.
Last reviewed by a Cleveland Clinic medical professional on 01/09/2022.
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