abducens nerve

Also known as: CN 6, CN VI, sixth cranial nerve

Learn about this topic in these articles:

major reference

  • Human nervous system
    In human nervous system: Abducens nerve (CN VI or 6)

    From its nucleus in the caudal pons, the abducens nerve exits the brainstem at the pons-medulla junction, pierces the dura mater, passes through the cavernous sinus close to the internal carotid artery, and exits the cranial vault via the…

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nervous system disorders

  • epilepsy
    In nervous system disease: Oculomotor, trochlear, and abducens nerves

    Compression of the oculomotor, trochlear, or abducens nerves may be caused by lesions, diabetes, vascular disease, head injury, infection, or neuropathy. In the brainstem, multiple sclerosis, stroke, Wernicke disease (see below Brainstem), and tumours are possible causes of compression. Double vision is the…

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vagus nerve

anatomy
Also known as: 10th cranial nerve, X cranial nerve
Also called:
X cranial nerve or 10th cranial nerve

vagus nerve, longest and most complex of the cranial nerves. The vagus nerve runs from the brain through the face and thorax to the abdomen. It is a mixed nerve that contains parasympathetic fibres. The vagus nerve has two sensory ganglia (masses of nerve tissue that transmit sensory impulses): the superior and the inferior ganglia. The branches of the superior ganglion innervate the skin in the concha of the ear. The inferior ganglion gives off two branches: the pharyngeal nerve and the superior laryngeal nerve. The recurrent laryngeal nerve branches from the vagus in the lower neck and upper thorax to innervate the muscles of the larynx (voice box). The vagus also gives off cardiac, esophageal, and pulmonary branches. In the abdomen the vagus innervates the greater part of the digestive tract and other abdominal viscera.

The vagus nerve has the most extensive distribution of the cranial nerves. Its pharyngeal and laryngeal branches transmit motor impulses to the pharynx and larynx; its cardiac branches act to slow the rate of heartbeat; its bronchial branch acts to constrict the bronchi; and its esophageal branches control involuntary muscles in the esophagus, stomach, gallbladder, pancreas, and small intestine, stimulating peristalsis and gastrointestinal secretions.

Vagus nerve stimulation, in which the nerve is stimulated with pulses of electricity, is sometimes used for patients with epilepsy or depression that is otherwise untreatable; the technique has also been explored for conditions such as Alzheimer disease and migraine.

Superficial arteries and veins of face and scalp, cardiovascular system, human anatomy, (Netter replacement project - SSC)
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The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Adam Augustyn.