Table of ContentsView AllTable of ContentsCranial Nerve FunctionsSymptomsDiagnosisTreatmentOutlook
Table of ContentsView All
View All
Table of Contents
Cranial Nerve Functions
Symptoms
Diagnosis
Treatment
Outlook
Even mild head trauma like aconcussioncan cause cranial nerve damage. The symptoms may appear immediately following the trauma, or they may not appear until days after the incident (for olfactory and facial nerve trauma). This delay may have to do with hematoma formation and resolution immediately after the trauma. The effects of cranial nerve injury may be temporary or permanent, depending on the nature of the injury.
This article covers the functions of the 12 cranial nerves and the symptoms you may see if one or more of these nerves are damaged. It also explains how cranial nerve damage is diagnosed and treated, and what to expect if you or someone you know has cranial nerve damage.
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There are a total of 12 cranial nerves. These nerves exit from the base of the brain and run through different parts of the face and head. The cranial nerves perform essential functions from providing sensation and controlling facial movements to initiating protective reflexes.
Since the cranial nerves control observable activities such as moving the eyes, chewing, and smiling, damage can be seen and felt when the nerve’s associated function is altered. Here is what the 12 cranial nerves do:
These nerves control essential functions of the head, face, neck, and more. While sometimes the damage is noticeable right away, it can also take hours to days for a disability to manifest. For example, if there is a growing blood clot pressing on a cranial nerve and the nerve begins to die, this can take some time to show up.
Symptoms of Cranial Nerve Damage
Different types of cranial nerve damage will cause different symptoms depending on which nerves are damaged. General symptoms of nerve damage include:
Damage to specific cranial nerves can produce specific types of symptoms:
How Is Cranial Nerve Damage Diagnosed?
Depending on the extent of the injury, healthcare providers may test the cranial nerves as part of aneurological exam, or they may perform specific tests to check the function of individual cranial nerves that may be injured.
To test for sensory and motor function of the cranial nerves, your healthcare provider may ask you to follow a finger with your eyes, say “ah,” and stick your tongue out. The provider may also touch certain parts of your face, use a tuning fork, assess yourpupillary response to light, and perform other tests.
If necessary, anMRImay be ordered because it can visualize the fine details of the nerves. ACTmay be necessary if damage to the structure around the nerves is suspected.
Treatment for Cranial Nerve Damage
If a cranial nerve is completely cut in two, it cannot be repaired. However, if it is stretched or bruised but remains intact, the nerve can recover. This takes time and can cause a variety of unpleasant symptoms including tingling and pain. These symptoms are a good sign that the nerve is healing.
Steroids may be used to decrease inflammation around a cranial nerve.Surgery is sometimes needed if a collection of blood, called a hematoma, is squeezing the nerve and leading to paralysis or dysfunction.
Neurologistsandneurosurgeonshave specialized assessments and interventions that address this type of nerve damage and should be consulted.
Outlook for Cranial Nerve Damage
Cranial nerve damage may cause partial or complete dysfunction, and the symptoms may be temporary or permanent.
One study looking at cranial nerve damage in patients with traumatic brain injury found that recovery tended to be seen more often among the participants in the younger age group and in people with delayed symptoms.
Nerve damage can be disabling and may require rehabilitation. The nerves that control eye movement and facial expressions may have a greater chance of regaining function than the olfactory, optic, and vestibulocochlear nerves.
Summary
The cranial nerves can be damaged from mild head injuries like concussions or more major injuries like fractures. Symptoms of cranial nerve damage can include pain, abnormal sensations, changes in vision, and weak or paralyzed muscles. They may show up immediately after the incident or may not appear until days or weeks later.
Talk to a healthcare provider immediately if you notice signs or symptoms of cranial nerve damage following head trauma. Treatment is available and, in some cases, the damage can be completely reversed, allowing you to make a full recovery.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Head injury - first aid.Basheer N, Varghese JC, Kuruvilla R, Alappat JP, Mathew J.A prospective study on the incidence and outcome of cranial nerve injuries in patients with traumatic brain injuries.Indian J Neurotrauma. 2021;18:45-50. doi:10.1055/s-0041-1724141University of Rochester Medical Center.Cranial neuropathies.Limphaibool N, Iwanowski P, Kozubski W, et al.Subjective and objective assessments of post-traumatic olfactory dysfunction.Front Neurol. 2020;11:970. doi:10.3389/fneur.2020.00970American Nurses Association.Use mnemonics to aid remembering and identifying abnormal findings.Romano N, Federici M, Castaldi A.Imaging of cranial nerves: a pictorial overview.Insights Imaging. 2019;10:33. doi:10.1186/s13244-019-0719-5NYU Langone Health.Medication for facial nerve paralysis.Huckhagel T, Riedel C, Rohde V, Lefering R.Cranial nerve injuries in patients with moderate to severe head trauma - Analysis of 91,196 patients from the TraumaRegister DGU® between 2008 and 2017.Clin Neurol Neurosurg. 2022;212:107089. doi:10.1016/j.clineuro.2021.107089
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Head injury - first aid.Basheer N, Varghese JC, Kuruvilla R, Alappat JP, Mathew J.A prospective study on the incidence and outcome of cranial nerve injuries in patients with traumatic brain injuries.Indian J Neurotrauma. 2021;18:45-50. doi:10.1055/s-0041-1724141University of Rochester Medical Center.Cranial neuropathies.Limphaibool N, Iwanowski P, Kozubski W, et al.Subjective and objective assessments of post-traumatic olfactory dysfunction.Front Neurol. 2020;11:970. doi:10.3389/fneur.2020.00970American Nurses Association.Use mnemonics to aid remembering and identifying abnormal findings.Romano N, Federici M, Castaldi A.Imaging of cranial nerves: a pictorial overview.Insights Imaging. 2019;10:33. doi:10.1186/s13244-019-0719-5NYU Langone Health.Medication for facial nerve paralysis.Huckhagel T, Riedel C, Rohde V, Lefering R.Cranial nerve injuries in patients with moderate to severe head trauma - Analysis of 91,196 patients from the TraumaRegister DGU® between 2008 and 2017.Clin Neurol Neurosurg. 2022;212:107089. doi:10.1016/j.clineuro.2021.107089
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus.Head injury - first aid.Basheer N, Varghese JC, Kuruvilla R, Alappat JP, Mathew J.A prospective study on the incidence and outcome of cranial nerve injuries in patients with traumatic brain injuries.Indian J Neurotrauma. 2021;18:45-50. doi:10.1055/s-0041-1724141University of Rochester Medical Center.Cranial neuropathies.Limphaibool N, Iwanowski P, Kozubski W, et al.Subjective and objective assessments of post-traumatic olfactory dysfunction.Front Neurol. 2020;11:970. doi:10.3389/fneur.2020.00970American Nurses Association.Use mnemonics to aid remembering and identifying abnormal findings.Romano N, Federici M, Castaldi A.Imaging of cranial nerves: a pictorial overview.Insights Imaging. 2019;10:33. doi:10.1186/s13244-019-0719-5NYU Langone Health.Medication for facial nerve paralysis.Huckhagel T, Riedel C, Rohde V, Lefering R.Cranial nerve injuries in patients with moderate to severe head trauma - Analysis of 91,196 patients from the TraumaRegister DGU® between 2008 and 2017.Clin Neurol Neurosurg. 2022;212:107089. doi:10.1016/j.clineuro.2021.107089
MedlinePlus.Head injury - first aid.
Basheer N, Varghese JC, Kuruvilla R, Alappat JP, Mathew J.A prospective study on the incidence and outcome of cranial nerve injuries in patients with traumatic brain injuries.Indian J Neurotrauma. 2021;18:45-50. doi:10.1055/s-0041-1724141
University of Rochester Medical Center.Cranial neuropathies.
Limphaibool N, Iwanowski P, Kozubski W, et al.Subjective and objective assessments of post-traumatic olfactory dysfunction.Front Neurol. 2020;11:970. doi:10.3389/fneur.2020.00970
American Nurses Association.Use mnemonics to aid remembering and identifying abnormal findings.
Romano N, Federici M, Castaldi A.Imaging of cranial nerves: a pictorial overview.Insights Imaging. 2019;10:33. doi:10.1186/s13244-019-0719-5
NYU Langone Health.Medication for facial nerve paralysis.
Huckhagel T, Riedel C, Rohde V, Lefering R.Cranial nerve injuries in patients with moderate to severe head trauma - Analysis of 91,196 patients from the TraumaRegister DGU® between 2008 and 2017.Clin Neurol Neurosurg. 2022;212:107089. doi:10.1016/j.clineuro.2021.107089
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