Pons: Function, Anatomy, Cranial Nerves and Conditions
Updated: 1 day ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is the pons?
The pons is the second-lowest section of the brainstem, just above the medulla oblongata. It links the brain with the spinal cord, relays nerve signals and helps control sleep-wake timing and breathing, and it connects with four cranial nerves. Pons conditions can cause poor coordination, double vision, vertigo or weakness, and sudden neurologic symptoms need emergency evaluation. [1]
What the research says
Most osmotic demyelination (central pontine myelinolysis) cases follow low blood sodium. A systematic review of 38 case series (541 patients) found hyponatremia was the most common predisposing factor (78%); 51.9% of patients recovered favorably and 24.8% died (Singh et al., European Journal of Neurology, 2014). [2]
Brainstem stroke raises the odds of swallowing problems. A meta-analysis of 10 studies (4,637 ischemic stroke patients) found 25.5% developed dysphagia, and brainstem stroke was linked to about twice the odds (OR 2.12, 95% CI 1.45–3.09) (Yang & Pan, PLOS One, 2022). [3]
The pons is the most common site when restless legs follows a brainstem stroke. A systematic review of 8 articles (19 patients) found symptoms improved or resolved in almost 90% of cases within days to 3 months (Kalampokini et al., Acta Neurologica Scandinavica, 2022). [4]
The pons is a common site for brainstem cavernous malformations. In a meta-analysis of 19 studies (940 patients) of surgery for brainstem cavernous malformations, most lesions were in the pons (475 patients); function improved in 56.7%, stayed stable in 28.6% and worsened in 12.6%, and mortality was 1% (Albalkhi et al., Neurosurg Rev, 2023) [5].
What is the pons?
The pons is a section of the brainstem. The brainstem forms a vital link between the brain above and the spinal cord below. [1]
The pons is the second-lowest section of the brainstem, located just above the medulla oblongata. It is a key merging point for several cranial nerves, which are nerves with direct connections to the brain. [1]
Because of its location and connections, the pons helps information travel between the brain, spinal cord, cerebellum and parts of the head and face. [1]
What does the pons do?
The pons contributes to several functions rather than acting alone. It provides a route for signals traveling to and from the brain and works with other brainstem structures and the cerebellum. [1]
It influences the sleep cycle and helps set the body’s level of alertness when waking. It also relays and regulates pain signals that provide sensation from areas of the body below the neck. [1]
The pons works with the cerebellum, which helps manage balance and movement, and cooperates with other brainstem areas involved in breathing. [1]
Pons-related role | What it means |
Signal relay | Helps carry information between the brain, spinal cord and other nervous-system structures |
Sleep and alertness | Contributes to sleep-wake timing and the level of alertness when waking |
Breathing coordination | Works with other brainstem structures involved in breathing |
Pain signaling | Relays and regulates signals that contribute to pain sensation below the neck |
Balance and movement connections | Connects with the cerebellum and helps coordinate information related to movement and balance |
The pons also contains neurotransmitters that facilitate brain function, particularly sleep. Its role is coordinated with many other structures, so a symptom should not be attributed to the pons without appropriate evaluation. [1]
Which cranial nerves connect with the pons?
Four of the 12 cranial nerves have key junctions in the pons: the trigeminal nerve, abducens nerve, facial nerve and vestibulocochlear nerve. [1]
Cranial nerve | Main functions described in relation to the pons |
Trigeminal nerve, CN V | Facial touch and pain sensation; muscles used for chewing |
Abducens nerve, CN VI | A muscle involved in eye movement; injury can cause double vision |
Facial nerve, CN VII | Most facial expressions and taste from the front of the tongue |
Vestibulocochlear nerve, CN VIII | Balance through the vestibular branch and hearing through the cochlear branch |
A problem near one of these nerve connections can affect a specific function, but symptoms can overlap across many neurologic conditions.
How does the pons help other organs and systems?
The pons helps the body by relaying sensory information and contributing to unconscious processes. Sleep-wake timing and breathing are two examples of functions that depend on coordinated activity across the brainstem and other structures. [1]
Pain sensation can also help a person respond to potentially harmful situations. The pons participates in relaying and regulating these signals, but it does not independently control every aspect of pain or breathing. [1]
Where is the pons located?
The pons is near the bottom of the skull. It sits just above the medulla oblongata, which continues downward and connects with the spinal cord through the opening at the base of the skull. [1]
Its position places it between the brain above and lower brainstem and spinal-cord structures below. The pons also connects with the cerebellum, which is important for balance and movement. [1]
What does the pons look like and how large is it?
The pons is beige or off-white and has a shape that resembles the upper stem of a branch of cauliflower. [1]
The dimensions described for the pons are approximately 27 millimeters tall, 38 millimeters wide and 25 millimeters deep. [1]
Dimension | Approximate measurement |
Height | 27 mm, or 1.06 inches |
Width | 38 mm, or 1.49 inches |
Depth | 25 mm, or 0.98 inches |
What is the pons made of?
The pons contains different types of nervous-system cells and structures, including nuclei. A nucleus is a cluster of nerve cells or brain cells with a shared function or connection. [1]
Neurons transmit and relay signals through electrical and chemical activity. A neuron includes a cell body, axon, dendrites and, in many neurons, a myelin coating around the axon. [1]
Glial cells support neurons rather than transmitting the main signals themselves. They help develop and maintain neurons, protect the nervous system, regulate its chemical balance and create myelin around some axons. [1]
What conditions can affect the pons?
Many brain conditions can affect the pons, while others involve the pons more specifically.
Condition category | Examples described in clinical education |
Vascular or traumatic | Stroke, concussion and other traumatic brain injuries |
Growths or structural problems | Brain tumors, including cancer |
Inflammatory or immune-related | Multiple sclerosis and other immune or inflammatory conditions |
Infectious | Bacterial, viral, parasitic or fungal infections |
Toxic | Heavy-metal poisoning and other toxins |
Inherited or present from birth | Congenital and genetic disorders |
Degenerative or movement-related | Multiple system atrophy and olivopontocerebellar atrophy |
Other neurologic syndromes | Central pontine myelinolysis and locked-in syndrome after trauma or stroke |
A condition affecting the pons is not necessarily a tumor or stroke. The cause must be determined through history, neurologic examination and appropriate testing.
What symptoms can pons conditions cause?
Symptoms depend strongly on which part of the pons is affected. Different areas support different nerve pathways and functions, so the pattern can vary.
Possible symptoms include ataxia, or lack of coordination; deafness; double vision; loss of touch, vibration, temperature or pain sensation; nystagmus; nausea and vomiting; paralysis; vertigo; and tinnitus.
Extensive damage to the pons causes paralysis of the entire body other than eye movement, a condition known as locked-in syndrome. [1]
These symptoms have many possible causes. A single symptom does not identify a pons problem.
Symptom or finding | What it may involve |
Ataxia | Difficulty coordinating movement or balance |
Double vision | Disrupted eye-movement control or another neurologic or eye condition |
Hearing change or deafness | Disruption involving hearing pathways or another cause |
Loss of sensation | Reduced ability to feel touch, vibration, temperature or pain |
Nystagmus | Involuntary eye movements |
Nausea or vomiting | May occur with vestibular or other neurologic problems |
Paralysis or weakness | May affect the face, head or specific body regions; extensive damage can cause severe paralysis |
Vertigo or tinnitus | Spinning sensation or ringing in the ears, with many possible causes |
Seek emergency help for sudden weakness or paralysis, new double vision, trouble speaking or swallowing, a severe sudden headache, seizure, fainting, difficulty breathing, sudden hearing or vision change or rapidly worsening neurologic symptoms.
How are pons conditions evaluated?
Evaluation begins with symptom timing, medical history, recent injury or infection, medicines and a neurologic examination. The clinician chooses tests based on the pattern of symptoms and examination findings.
Test | General purpose |
MRI | Provides detailed images of the brainstem and nearby structures |
CT scan | Produces cross-sectional images and may help evaluate urgent structural concerns |
Blood tests | May identify immune problems, infection, toxins or heavy metals |
EEG | Records electrical activity in the brain |
Electromyogram | Evaluates electrical activity in muscles and related nerve conduction |
Evoked potentials | Measures responses to sensory stimulation |
Genetic testing | May help identify an inherited condition in appropriate circumstances |
PET scan | Provides metabolic or functional imaging information when clinically indicated |
Not every person needs every test. A scan or laboratory result must be interpreted with symptoms, examination findings and medical history.
How are pons conditions treated?
Treatment varies widely because pons conditions have different causes. Some respond to medication, while others require advanced care such as surgery. Some conditions cannot be cured or directly treated, so care may focus on symptoms, function and safety.
There is no single treatment for all conditions affecting the pons. A neurologist or another appropriate specialist can explain what the findings mean and which treatment options fit the cause.
Do not assume that a symptom, online image or isolated test result identifies a specific pons condition. Avoid starting, stopping or changing medication without professional guidance.
How can someone reduce risk to brain health?
Some conditions affecting the pons are preventable, while others occur unpredictably. General measures described for brain health include eating a balanced diet, staying physically active, maintaining a healthy weight, using safety equipment such as helmets and managing chronic conditions such as high blood pressure. [1]
Unusually high or low vitamin levels can affect the brain and nervous system. [1]
These actions may reduce risk in some situations but cannot prevent every neurologic condition. They also do not replace evaluation after new symptoms, head injury or an abnormal test.
General measure | Why it may help |
Balanced nutrition | Supports brain and nervous-system health and circulatory health |
Physical activity | Supports cardiovascular health and may reduce some risk factors |
Safety equipment | Helps reduce the chance of concussion and traumatic brain injury |
Chronic-condition care | Managing conditions such as high blood pressure may reduce risk of further brain injury |
Prompt evaluation | Helps distinguish urgent neurologic problems from less urgent causes |
What questions should you ask about the pons and your symptoms?
Questions about the pons and your symptoms can cover possible sources, exam findings, whether imaging or blood tests are needed, which specialist to see and when to seek emergency care.
Could my symptoms come from the pons, another part of the brainstem, the cerebellum, the inner ear or another condition?
What does my neurologic examination show?
Would MRI or CT be appropriate, and what question is the test meant to answer?
Do I need blood tests for infection, inflammation, toxins or other causes?
Could a recent head injury, infection or medicine be contributing?
Should I see a neurologist, neuro-ophthalmologist, ear specialist or another clinician?
What symptoms should prompt emergency care?
What activities are safe while a new neurologic symptom is being evaluated?
Conclusion: A small but highly connected structure
The pons is a small but highly connected part of the brainstem. It links the brain with the spinal cord, works with the cerebellum and other brainstem structures, contributes to sleep-wake timing and breathing, and relays signals related to pain, sensation, movement and balance. [1]
Its connections with cranial nerves V through VIII help support facial sensation, chewing, eye movement, facial expression, taste, balance and hearing. Because many conditions can affect the same pathways, symptoms such as vertigo, double vision, weakness, nausea or coordination changes require context rather than self-diagnosis. [1]
Frequently Asked Questions
What is the pons?
The pons is the second-lowest section of the brainstem. It sits above the medulla oblongata and helps connect the brain with the spinal cord.
What does the pons control?
The pons contributes to sleep-wake timing, alertness when waking, breathing coordination, pain-signal relay and communication with the cerebellum. It works with other brain structures rather than controlling these functions alone.
Which cranial nerves connect with the pons?
The trigeminal nerve, abducens nerve, facial nerve and vestibulocochlear nerve have key junctions in the pons. They support facial sensation, chewing, eye movement, facial expression, taste, balance and hearing.
What are symptoms of a pons problem?
Possible symptoms include ataxia, hearing loss, double vision, loss of sensation, nystagmus, nausea, vomiting, paralysis, vertigo and tinnitus. Symptoms depend on the affected area and have many possible causes.
Can a pons problem cause vertigo?
Yes, a pons condition can be associated with vertigo, but vertigo also has many other possible causes. New, severe or neurologic-associated vertigo should be evaluated promptly.
Can a pons problem affect breathing?
The pons works with other brainstem structures involved in breathing. Difficulty breathing is an emergency symptom and should not be attributed to a pons condition without immediate medical assessment.
How is the pons examined?
Clinicians may use MRI, CT, blood tests, EEG, electromyogram, evoked potentials, genetic testing or PET, depending on the symptoms and examination.
What is the treatment for a pons condition?
Treatment depends on the cause. Some conditions respond to medication, some require advanced care such as surgery and some are managed mainly by treating symptoms and supporting function.
Can someone prevent pons problems?
Not all pons conditions are preventable. General brain-health measures include balanced nutrition, physical activity, injury prevention and management of chronic conditions such as high blood pressure.
When are pons symptoms an emergency?
Seek emergency help for sudden weakness or paralysis, new double vision, trouble speaking or swallowing, severe sudden headache, seizure, fainting, difficulty breathing, sudden hearing or vision changes or rapidly worsening neurologic symptoms.
Related Reading
Pontine Stroke: Recognizing and Managing a Brainstem Emergency explains the warning signs and treatment of a stroke in the pons.
Locked-in Syndrome: Understanding Life Behind Total Paralysis describes the rare paralysis that can follow damage to the pons.
Understanding the Medulla Oblongata: Anatomy, Function, and Health covers the brainstem section just below the pons and its vital roles.
Understanding Your Cranial Nerves: A Guide to the 12 Pairs explains all 12 cranial nerves, including those that start in the pons.
References
Cleveland Clinic. What Is the Pons? Cleveland Clinic. Last updated May 15, 2022. https://my.clevelandclinic.org/health/body/23003-pons
Singh TD, Fugate JE, Rabinstein AA. Central pontine and extrapontine myelinolysis: a systematic review. Eur J Neurol. 2014;21(12):1443-1450. PMID 25220878. https://doi.org/10.1111/ene.12571
Yang C, Pan Y. Risk factors of dysphagia in patients with ischemic stroke: a meta-analysis and systematic review. PLoS One. 2022;17(6):e0270096. PMID 35709228. https://doi.org/10.1371/journal.pone.0270096
Kalampokini S, Poyiadjis S, Vavougios GD, et al. Restless legs syndrome due to brainstem stroke: a systematic review. Acta Neurol Scand. 2022;146(5):440-447. PMID 36063288. https://doi.org/10.1111/ane.13702
Albalkhi I, Shafqat A, Bin-Alamer O, et al. Long-term functional outcomes and complications of microsurgical resection of brainstem cavernous malformations: a systematic review and meta-analysis. Neurosurg Rev. 2023;46(1):252. PMID 37726558. https://doi.org/10.1007/s10143-023-02152-8
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition.
Comments