Arnold's nerve

Arnold's nerve, also known as the auricular branch or mastoid branch, of the vagus nerve (CN X) is a small sensory nerve supplying the skin of the external acoustic meatus. 

Terminology

The greater occipital nerve has also been known in the past - confusingly - as the nerve of Arnold.

The use of the eponym 'Arnold' for the greater occipital nerve is now felt to be erroneous, based upon a historical misattribution. Therefore, by extension, the use of the term Arnold neuralgia, for occipital neuralgia, is also suspect and should be discarded ⁵. 

Origin and course

Arnold's nerve originates from the superior ganglion of the vagus nerve and also has a small contribution from the inferior ganglion of the glossopharyngeal nerve. It branches from the vagus nerve and ascends through the mastoid canaliculus (a small bony canal joining the pars vascualris and facial canal) to join the distal facial canal just superior to the stylomastoid foramen. It then passes superiorly through the mastoid before running laterally along the floor of the middle ear and exiting the skull to the preauricular soft tissues via the tympanomastoid fissure. 

Innervation

Arnold's nerve innervates the small parts of the external acoustic meatus and is the source of jugulotympanic paraganglioma from the non-chromaffin paraganglion cells, which are found along the nerve.

It is also responsible for the referred otalgia through the vagus nerve (CN X), in the case of laryngeal pathology.

History and etymology

Named after Philipp Friedrich Arnold, German anatomist (1803-1890) ^1,3. Also known as the alderman's nerve on the belief that stimulating the external auditory canal will stimulate gastric emptying; the aldermen who ate too much for lunch would wiggle their fingers in the external canal to relieve their epigastric discomfort ⁴.

Related pathology

• jugulotympanic paraganglioma