World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0000229296
Reproduction Date:

Title: Pons  
Author: World Heritage Encyclopedia
Language: English
Subject: Millard–Gubler syndrome, Locus coeruleus, Cochlear nucleus, Vestibulospinal tract, Cerebellum
Collection: Pons
Publisher: World Heritage Encyclopedia


Diagram showing the positions of the three principal subarachnoid cisternæ (pons visible at center)
Anteroinferior view of the medulla oblongata and pons
Part of Brain stem
pontine arteries
transverse and lateral pontine veins
MeSH A08.
NeuroNames hier-538
NeuroLex ID Pons
Anatomical terms of neuroanatomy

The pons is part of the brainstem, and in humans and other bipeds lies between the midbrain (above) and the medulla oblongata (below) and in front of the cerebellum.

The pons is also called the pons Varolii ("bridge of Varolius"), after the Italian anatomist and surgeon Costanzo Varolio (1543–75).[1] This white matter includes tracts that conduct signals from the brain down to the cerebellum and medulla, and tracts that carry the sensory signals up into the thalamus.[2]

The pons in humans measures about 2.5 cm or 1 inch in length. Most of it appears as a broad anterior bulge rostral to the medulla. Posteriorly, it consists mainly of two pairs of thick stalks called cerebellar peduncles. They connect the cerebellum to the pons and midbrain.[2]

The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.[2]

Within the pons is the pneumotaxic center, a nucleus that regulates the change from inhalation to exhalation.[2]

The pons is implicated in sleep paralysis, and also plays a role in generating dreams.


  • Structure 1
    • Development 1.1
    • Nucleus 1.2
  • Function 2
  • Clinical significance 3
  • Other animals 4
    • Evolution 4.1
  • Additional images 5
  • References 6
  • External links 7


The pons can be broadly divided into two parts: the basilar part of the pons, located ventrally, and the pontine tegmentum, located dorsally.


During embryonic development, the metencephalon develops from the rhombencephalon and gives rise to two structures: the pons and the cerebellum.[2] The alar plate produces sensory neuroblasts, which will give rise to the solitary nucleus and its special visceral afferent (SVA) column; the cochlear and vestibular nuclei, which form the special somatic afferent (SSA) fibers of the vestibulocochlear nerve, the spinal and principal trigeminal nerve nuclei, which form the general somatic afferent column (GSA) of the trigeminal nerve, and the pontine nuclei which relays to the cerebellum.

Basal plate neuroblasts give rise to the abducens nucleus, which forms the general somatic efferent fibers (GSE); the facial and motor trigeminal nuclei, which form the special visceral efferent (SVE) column, and the superior salivatory nucleus, which forms the general visceral efferent fibers of the facial nerve.


A number of cranial nerve nuclei are present in the pons:


The functions of these four nerves include sensory roles in hearing, equilibrium, and taste, and in facial sensations such as touch and pain, as well as motor roles in eye movement, facial expressions, chewing, swallowing, and the secretion of saliva and tears.[2]

Clinical significance

  • Central pontine myelinosis is a demyelination disease that causes difficulty with sense of balance, walking, sense of touch, swallowing and speaking. In a clinical setting, it is often associated with transplant or rapid correction of blood sodium. Undiagnosed, it can lead to death or locked-in syndrome.

Other animals


The pons first evolved as an offshoot of the medullary reticular formation.[3] Since lampreys possess a pons, it has been argued that it must have evolved as a region distinct from the medulla by the time the first agnathans appeared, 505 million years ago.[4]

Additional images


  1. ^ Henry Gray (1862). Anatomy, descriptive and surgical. Blanchard and Lea. pp. 514–. Retrieved 10 November 2010. 
  2. ^ a b c d e f Saladin Kenneth S.(2007)
  3. ^ Medical NeurosciencePritchard and Alloway
  4. ^ Comparative vertebrate neuroanatomy: evolution and adaptationButler and Hodos

Saladin Kenneth S.(2007) Anatomy & physiology the unity of form and function. Dubuque, IA: McGraw-Hill

  • Pritchard, TE and Alloway, D (1999). Medical neuroscience. Hayes Barton Press.  
  • Butler, AB and Hodos, W (2005). Comparative vertebrate neuroanatomy: evolution and adaptation. Wiley-Blackwell.  

External links

  • Diagram at UCC
  • Stained brain slice images which include the "Pons" at the BrainMaps project
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.