Intercostal nerve: anatomy and pathologies

The intercostal nerves are neurological branches of thoracic nerve trunks. They are from of the spinal cord and are responsible for theinnervation of intercostal muscles and abdominal wall. They also play an important role in respiration. A trauma or an lesion at the level of these nerves can lead to symptoms up mimic heart problems ou serious pulmonary. So how to explain this? How to disentangle the true from the false? For more, stay until the end of this article.



To put it simply, a intercostal nerve is a nerve that path between the intercostal spaces, that is to say between two upper and lower ribs. In humans, there are eleven pairs, located on either side of the spine. They innervate la most of the chest wall et abdominal.


intercostal nerve




Origin of the intercostal nerve


The intercostal nerves are the anterior branches of nerves thoracic spines (T1-T11). They are born at the exit of the intervertebral foramen (also called hole of conjugation). The intervertebral foramina are small holes located between two vertebrae through which the nerves exit outside the spinal column.


After foraminal passage, the twelve pairs of thoracic spinal nerves (T1-T12) divide into two branches: ventral (anterior) and dorsal (posterior). The ventral branches of T1-T11 form the intercostal nerves that enter the intercostal spaces. While, the ventral branch of T12 forms the subcostal nerve which runs under the 12th rib.


Each intercostal nerve immediately enters the space between two ribs, called the intercostal space. It lies between the lower part of the overlying rib (top), above the underlying rib (bottom), and between the intercostal muscles.


The intercostal nerves are composed of anterior motor nerve fibers, posterior sensory nerve fibers, and postganglionic sympathetic nerves (nerve ganglia).


Throughout his journey, each intercostal nerve is associate to one artery and at a vein, forming what is called the neurovascular bundle.


The main branches of the intercostal nerves are the anterior and lateral cutaneous branches. These branches innervate the skin and the intercostal muscles.


Course of the intercostal nerve


In intercostal spaces, the intercostal nerves walk between the intercostal muscles with corresponding arteries and veins.


The nerves then run to the lower border of the underlying rib and run below the intercostal artery. They terminate at the anterior end of the intercostal space giving rise to a cutaneous branch (called the anterior perforating cutaneous branch).


In the abdominal wallThey walk between the internal oblique and transverse muscles. If the course of the first intercostal nerves is globally horizontal, that of the intermediate nerves and especially of the last intercostal nerves is oblique forwards and downwards. The eleventh intercostal nerve which originates near the eleventh vertebrate thoracic ends below the umbilicus.


Functions of the intercostal nerve


The intercostal nerves are independent and parallel to each other. Their posterior root is sensory and carries the nerve ganglion (or spinal ganglion). Their anterior root, on the other hand, is motor.


Sensory fibers transmit information from sensory receptors in the skin and muscles to the spinal cord, while their motor fibers transmit signals from the spinal cord to muscles and glands.


They innervate the intercostal muscles and abdominal wall, and are involved in breathing.


The external, internal and intimate intercostal muscles, as well as the subcostal and levator muscles of the ribs are innervated by each of the corresponding nerves. The transverse thoracic muscles are also innervated by the intercostal nerves.


The dorsal branches of the intercostal nerves pass posteriorly to innervate much of the skin (in the thorax and abdomen), including the mammary glands (the breasts) through the fourth, fifth, and sixth nerves.


The rectus, external oblique and transverse abdominis muscles are also innervated by the intercostal nerves (by the last five intercostal nerves).



The different pathologies of the intercostal nerve


Intercostal neuralgia


La intercostal neuritis is the pathology la most common of the intercostal nerves. It is a painful pathology characterized by lesion or inflammation one or more intercostal nerves. These pains are related to the irritation of an intercostal nerve.


La intercostal neuralgia can create a wide variety of symptoms. the most common symptom is a pain, type of electric shock, dysesthesia or burning, at the level of the thorax. In 70% of cases, the pain occurs on one side only. When the pain is particularly acute, it can cause breathing difficulties.


The intensity of the pain is extremely variable, it can last a few minutes or a few hours, the pain can be long and diffuse or brief and intense. It can even sometimes be confused with a myocardial infarction, which is a real medical emergency.


It is most often benign in connection with a vertebral pathology such as osteoarthritis of the spine, or may appear after a trauma or a false movement (for example a rib fracture, a sprain of the intercostal muscles, a bad position at night…). However, it is in rare cases related to a tumor pathology, infection or shingles.


Individuals who perform high impact sports are more likely to suffer from intercostal neuralgia.


This sensation can also be accompanied by intense pain when palpating the intercostal muscles, continuous pain in the rib cage, general rigidity of the chest and shortness of breath following these breathing difficulties .


To learn more about intercostal neuralgia, see the following article.


Post-herpetic neuralgia


THEherpes is a disease caused by varicella zoster virus. In a person who has had chickenpox, the virus remains in the body in a dormant state. And it's there reactivation of this one which gives the disease. Only people who have already suffered from chickenpox during childhood can get shingles. This reactivation of the varicella virus mainly affects people over the age of 50.


La neuralgia is the complication la more common after shingles. This complication mostly affects the intercostal nerves or facial nerves.


Some warning signs are characteristic of the onset of shingles. Three to four days before the reactivation of the virus, the person may feel a feeling unwell with chills, fever, nausea, or diarrhea.


Then some skin signs appear, pustules in clumps, leading to burns and itching on the side of the chest or back. These pustules are very painful and can last several weeks before disappearing.


Neuralgia after rib fracture


It most often results from a trauma. Rib fractures can cause of injury of intercostal nerves. It causes pain in the chest. Depending on the degree of injury, there may be sensory or motor problems (such as decreased intercostal muscle mobility).


Other pathologies


Of course, there are still many other causes of trauma to the intercostal nerves.


  • The intercostal muscle cramps sudden onset and short-lived. They usually disappear within half an hour.
  • The intercostal muscle tears result from trauma or intensive exercise.
  • The rib sprains can occur by direct contusion, by sudden movement of rotation, by effort of stretching or by compression of the thorax...





To relieve pain in the intercostal neuralgia, drug treatments (analgesics, anti-inflammatories and muscle relaxants) are very effective, both on pain and muscle tension. Sessions of physiotherapy can be offered.


The treatment with antiretroviral drugs orally is usually sufficient for post-herpetic neuralgia.


In case de rib fracture,immobility must be maintained. Neurological injuries are treated according to the severity of the injury.







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