They play a critical role in breathing and are responsible for thehiccup reflex.
The phrenic nerves also have sensory and sympathetic functions.
In addition, they are often responsible for the referred pain to the shoulder that can accompany abdominal disorders.
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The phrenic nerves run from the cervical spine to the diaphragm.
The phrenic nerves originate from the cervical spine nerves C3, C4, C5.
The phrenic nerves then insert into the left dome and right dome of the diaphragm, respectively.
This variant may also receive branches from the brachial andcervical plexus.
Pain detected by the phrenic nerves is often felt in another region (referred pain).
This finding could have important implications with regard to nerve stimulation practices.
Hiccups
The phrenic nerve is responsible for thehiccup reflex.
Understanding the anatomy of the phrenic nerve can be helpful in looking for potential causes.
Central nervous system causes are possible as well.
This can be temporary or permanent depending on whether the nerve is only injured or if it is disrupted.
When the phrenic nerve is disrupted, the recovery depends upon several different factors.
These can be broken down by mechanism.
Spinal cord injuries, especially above C5, often lead to paralysis of the diaphragm.
When the inferior vena cava is clamped during liver transplantation, the nearby right phrenic nerve is often damaged.
Symptoms are often more apparent in children who have weaker muscles and a more compliant chest.
Other symptoms may include chest wall pain, cough, fatigue, anxiety, and morning headache.
The diagnosis is often made by visualizing the abnormal motion of the diaphragm on ultrasound or fluoroscopically.
Pulmonary function tests will show a restrictive pattern (restrictive lung disease in contrast to obstructive).
For some people with unilateral phrenic nerve injury, no treatment is necessary.
The accessory muscles of inspiration, such as the intercostal and abdominal muscles, provide some help.
With some injuries causing only partial paralysis, function may return in time.
Summary
The phrenic nerves play an important role in breathing.
These nerves are vulnerable to injury and can cause serious problems when damaged.
Paralysis of the diaphragm is brought on by damage to both phrenic nerves.
This can happen during certain kinds of surgery or trauma.
Some kinds of infectious and neuromuscular diseases can also affect the phrenic nerves.
Damaged phrenic nerves can be treated with ventilation, diaphragm pacemakers, or surgery.
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