pons

1. A slender tissue joining two parts of an organ.
2. A band of nerve fibers on the ventral surface of the brain stem that links the medulla oblongata and the cerebellum with upper portions of the brain. Also called pons Varolii.

[Latin pōns, bridge.]

A structure dorsal to the medulla and intimately related to the pathways to the cerebrum. The cranial nerves whose nuclei lie in the pons are the trigeminal, abducens, and facial nerves, and part of the acoustic nerve. The pons is intimately related to the medulla, has the same blood vessel supply, and is involved in many lesions that affect the medulla. It is especially involved with the cerebellar manifestations of disease and may cause serious muscular incoordination in motor function of the head, neck, and facial structures.

Any bridge-like structure that joins two parts of an organ.

1. that part of the metencephalon lying between the medulla oblongata and the midbrain, ventral to the cerebellum. See also brainstem.
2. slip of tissue connecting two parts of an organ.

• p. varolii — pons (1).

Brain: Pons
Diagram showing the positions of the three principal subarachnoid cisternæ. (Pons visible at center.)
Anteroinferior view of the medulla oblongata and pons.
Gray's	subject #187 785
Part of	Brain stem
Artery	pontine arteries
Vein	transverse and lateral pontine veins
NeuroNames	hier-538
MeSH	Pons
NeuroLex ID	birnlex_733

For other uses, see Pons (disambiguation).

The pons (sometimes pons Varolii after Costanzo Varolio) is a structure located on the brain stem. It is cranial to (up from) the medulla oblongata, caudal to (down from) the midbrain, and ventral to (in front of) the cerebellum. In humans and other bipeds this means it is above the medulla, below the midbrain, and anterior to the cerebellum. The pons regulates relaxation, and is associated with the sense of higher purpose.

Contents 1 Cranial nerve nuclei 2 Related diseases 3 Additional images 4 References 5 External links

Cranial nerve nuclei

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

• mid-pons: The chief or pontine nucleus of the trigeminal nerve sensory nucleus (V)
• mid-pons: the motor nucleus for the trigeminal nerve (V)
• lower down in the pons: abducens nucleus (VI)
• lower down in the pons: facial nerve nucleus (VII)
• lower down in the pons: vestibulocochlear nuclei (vestibular nuclei and cochlear nuclei) (VIII)

Related diseases

• Central pontine myelinosis, 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. Undiagnosed it can lead to death or locked in syndrome.

Additional images

Location and topography of Pons(Animation)	Scheme showing the connections of the several parts of the brain.	Superficial dissection of brain-stem. Lateral view.	Superficial dissection of brain-stem. Ventral view.
Axial section of the pons, at its upper part.	Dissection showing the projection fibers of the cerebellum.	Sagittal section through right cerebellar hemisphere. The right olive has also been cut sagitally.	Scheme of roof of fourth ventricle. The arrow is in the foramen of Majendie.
Mesal aspect of a brain sectioned in the median sagittal plane.	Coronal section of brain immediately in front of pons.	Hind- and mid-brains; postero-lateral view.	Median sagittal section of brain.
Dissection showing the course of the cerebrospinal fibers.	Terminal nuclei of the cochlear nerve, with their upper connections.	Terminal nuclei of the vestibular nerve, with their upper connections.	The hypophysis cerebri in position. Shown in sagittal section.
Pituitary and pineal glands	Axial section of the Brainstem (Pons) at the level of the Facial Colliculus	Human cerebrum lateral view	Human brain frontal (coronal) section
Human brainstem anterior view

References

External links

• Diagram at UCC
• BrainMaps at UCDavis Pons

v • d • e Nervous system (TA A14, GA 9) Central nervous system Meninges Spinal cord Brain: Rhombencephalon (Medulla oblongata, Pons, Cerebellum) • Mesencephalon • Prosencephalon (Diencephalon, Telencephalon) Peripheral nervous system Somatic Sensory nerve • Motor nerve • Cranial nerves • Spinal nerves Autonomic Sympathetic • Parasympathetic • Enteric nervous system central nervous system navs: anat/physio/dev, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc peripheral nervous system navs: anat/histo/physio/dev, noncongen PNS somatic/autonomic/congen/neoplasia, symptoms+signs/eponymous, proc

v • d • e Human brain, rhombencephalon, metencephalon: pons (TA A14.1.05.101-604, GA 9.785) Dorsal/ (tegmentum) Surface Cerebellopontine angle · Superior medullary velum · Sulcus limitans · Medial eminence · Facial colliculus White: Sensory/ascending Trapezoid body/VIII · Trigeminal lemniscus (Dorsal trigeminal tract, Ventral trigeminal tract) · Medial lemniscus · Lateral lemniscus MLF, III, IV and VI: Vestibulo-oculomotor fibers Anterior trigeminothalamic tract · Central tegmental tract White: Motor/descending ICP (Vestibulocerebellar tract) MLF, III, IV and VI: Vestibulospinal tract (Medial vestibulospinal tract, Lateral vestibulospinal tract) Grey: Cranial nuclei afferent: GSA: Principal V/Spinal V · VIII-c (Dorsal, Anterior)/VIII-v (Lateral, Superior, Medial, Inferior) efferent: SVE: Motor V  · VII · GSE: VI · GVE: VII: Superior salivary nucleus Other grey Apneustic center · Pneumotaxic center (Medial parabrachial nucleus) · Lateral parabrachial nucleus · Superior olivary nucleus · Caerulean nucleus Ventral/ (base) Grey Pontine nuclei White: Motor/descending Corticospinal tract · Corticobulbar tract · Corticopontine fibers MCP (Pontocerebellar fibers) Surface Basilar sulcus Other grey: Raphe/ reticular Reticular formation (Caudal, Oral, Tegmental, Paramedian) · Raphe nuclei (Median)

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