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Information about Phrenic Nerve

Nerve:
The phrenic nerve and its relations with the vagus nerve. (Phrenic labeled at upper left.)
Plan of the cervical plexus. (Phrenic labeled at bottom right.)
Latinnervus phrenicus
subject #210 928
FromC3-C5 of cervical plexus
Dorlands/Elsevier n_05/12566505
The phrenic nerve arises from the third, fourth, and fifth cervical spinal nerves (C3-C5) in humans. It arises from the fifth, sixth and seventh cervical spinal nerves (C5-7) in most domestic animals.

Function

The phrenic nerve is made up mostly of motor nerve fibres for producing contractions of the diaphragm. In addition, it provides sensory innervation for many components of the mediastinum and pleura, as well as the upper abdomen, especially the liver and gall bladder.

Path

Both phrenic nerves run from C3, C4 and C5 along the anterior scalene muscle deep to the carotid sheath. Both these nerves supply motor fibres to the diaphragm and sensory fibres to the fibrous pericardium, mediastinal pleura and diaphragmatic peritoneum.

The pericardiacophrenic artery and vein(s) travel with the phrenic nerve.

Clinical relevance

Pain arising from structures served by the phrenic nerve is often "referred" to other somatic regions served by spinal nerves C3-C5. For example, a subphrenic abscess (beneath the diaphragm) might cause a patient to feel pain in the right shoulder.

Irritation of the phrenic nerve (or the tissues supplied by it) leads to the hiccup reflex. A hiccup is a spasmodic contraction of the diaphram, which pulls air against the closed folds of the larynx.

The phrenic nerve must be identified during thoracic surgery and preserved. It passes anterior to the hilum of the corresponding lung, and therefore can be identified easily. Severing the phrenic nerve will paralyse that half of the diaphragm. Breathing will be made more difficult but will continue provided the other nerve is intact.

Additional images


Transverse section of thorax, showing relations of pulmonary artery.

The arch of the aorta, and its branches.

Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries.

The right brachial plexus with its short branches, viewed from in front.


External link

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Nerves of head and neck: the cervical plexus
superficiallesser occipital • greater auricular • transverse cervical • supraclavicular
deepansa cervicalis • phrenic
The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the
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Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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The cervical plexus is a plexus of the ventral rami of the first four cervical spinal nerves which are located from C1 to C4 cervical segment in the neck. They are located laterally to the transverse processes between prevertebral muscles from the medial side and vertebral (m.
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. The spinal nerve is the bit that passes out of the vertebrae through the intervertebral foramen.
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This article has been tagged since September 2007.

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diaphragm is a sheet of muscle extending across the bottom of the ribcage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration.
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The mediastinum is a non-delineated group of structures in the thorax (chest), surrounded by loose connective tissue. It is the central compartment of the thoracic cavity.
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pleurae. The outer pleura is attached to the chest wall and is known as the parietal pleura; the inner one is attached to the lung and other visceral tissues and is known as the visceral pleura.
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liver is an organ present in vertebrates and some other animals. It plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, and detoxification.
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The gallbladder (or cholecyst, sometimes gall bladder) is a pear-shaped organ that stores about 50 ml of bile (or "gall") until the body needs it for digestion.
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The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior. They originate from the transverse processes from the cervical vertebrae of CII to CVII and insert onto the first and second ribs.
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The carotid sheath is an anatomical term for the fibrous connective tissue that surrounds the internal carotid artery and related structures in the neck.

Structure


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The brachiocephalic artery (or brachiocephalic trunk or innominate artery) is an artery of the mediastinum that supplies blood to the right arm and the head and neck.
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In human anatomy, the subclavian veins are two large veins, one on either side of the body. Its diameter is approximately that of a man's small finger. It is divided into right and left subclavian vein.
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lungs flank the heart and great vessels in the chest cavity.[1]]]

The lung is the essential respiration organ in air-breathing vertebrates, the most primitive being the lungfish.
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thorax is a division of an animal's body that lies between the head and the abdomen.

In mammals, the thorax is the region of the body formed by the sternum, the thoracic vertebrae and the ribs. It extends from the neck to the diaphragm, not including the upper limbs.
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The caval opening is a hiatus in the diaphragm of humans through which passes the inferior vena cava, the wall of which is adherent to the margins of the opening, and some branches of the right phrenic nerve.
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The right atrium (in older texts termed the "right auricle") is one of four chambers (two atria and two ventricles) in the human heart. It receives de-oxygenated blood from the superior and inferior vena cavae and the coronary sinus, and pumps it into the right ventricle through
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The left ventricle is one of four chambers (two atria and two ventricles) in the human heart. It receives oxygenated blood from the left atrium via the mitral valve, and pumps it into the aorta via the aortic valve.
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The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.

Layers

There are two layers to this sac: the fibrous pericardium and the serous pericardium.
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In higher vertebrates, the peritoneum is the serous membrane that forms the lining of the abdominal cavity - it covers most of the intra-abdominal organs. It is composed of a layer of mesothelium supported by a thin layer of connective tissue.
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The pericardiacophrenic artery is a long slender branch of the internal thoracic artery. It accompanies the phrenic nerve, between the pleura and pericardium, to the diaphragm, to which it is distributed; it anastomoses with the musculophrenic and inferior phrenic arteries.
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Referred pain is a very unpleasant sensation localized to an area separate from the site of the causative injury or other painful stimulation. Often, referred pain arises when a nerve is compressed or damaged at or near its origin.
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Hiccup
Classifications and external resources

ICD-10 R 06.6
ICD-9 786.8

A hiccup or hiccough (normally pronounced "HICK-up" (IPA: /ˈhɪkʌp/
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The larynx (plural larynges), colloquially known as the voicebox, is an organ in the neck of mammals involved in protection of the trachea and sound production.
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surgery (from the Greek χειρουργική meaning "hand work") is the medical specialty that treats diseases or injuries by operative manual and instrumental treatment.
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A hilum (formerly called a hilus) is a depression or pit where strutures are attached.
  • In human anatomy, the hilum is part of an organ where structures such as blood vessels and nerves enter.

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