What to know about cranial nerve 7 (facial nerve) (2023)

Cranial nerve 7, also called the facial nerve, controls movement of the face, including the forehead, eyelids, cheeks, mouth, and jaw. The facial nerve can become damaged due to trauma, inflammation, infection or disease.

Damage to this nerve can cause facial weakness, as well as insufficient tears and saliva, decreased taste, and decreased sensation behind the ears. Depending on the cause, treatment for cranial nerve damage 7 can include medications, physical therapy, electrical stimulation techniques, and surgery.

This article will discuss the structure and function of cranial nerve 7, injuries and deficiencies of this nerve, and when to see a doctor.

What to know about cranial nerve 7 (facial nerve) (1)


Cranial nerve 7 emergeso tronco cerebralat the level of the pons, which is the middle part of the brainstem. The left and right cranial nerves 7 are symmetrical in structure and function.

From the brainstem, located at the back of the neck, the nerve coils towards the face. Cranial nerve 7 has many branches that lead to the small muscles of the face, the glands in the eyes and mouth, and the sensory fibers behind the ear.

If a 7th cranial nerve is damaged, it will cause weakness on the entire side of the face, including the forehead.

The Difference Between Bell's Palsy and Stroke


Cranial nerve 7 has several functions. The most prominent function is the movement of the face. Facial movements include blinking, opening the eyes, raising the eyebrows, smiling, puffing out the cheeks, and pursing the lips.

Some of these movements are voluntary (on purpose) and some are involuntary (not on purpose). Involuntary movements include blinking when something approaches your eyes.Movement is controlled in the following ways:

  • Left cranial nerve 7 controls movement on the left side of the face.
  • Right cranial nerve 7 controls movement on the right side of the face.

This nerve also helps produce tears and saliva, contributes to the sense of taste, and has some sensory function behind the ears.

injury or disability

Sometimes medical problems or injuries can cause cranial nerve 7 function to decrease permanently or temporarily. This causes paralysis (weakness) of some facial movements. Damage to cranial nerve 7 can cause partial paralysis (paresis) complete paralysis (plegia) of the affected parts of the face.

bell's palsyit is the most common condition that affects cranial nerve 7. This condition causes weakness on one side of the face. It is thought to be associated with inflammation or infection, but is generally considered idiopathic, meaning it has no identifiable cause.

Bell's palsy can be distressing, but it's not dangerous and usually goes away after weeks or months. Other causes of facial weakness (such as stroke or infection) often need to be considered and ruled out before Bell's palsy is diagnosed. Treatment with oral steroids can speed recovery.

Other problems that can affect cranial nerve 7 include trauma, which can be the result of an accident, dental condition, or surgical complication.Sometimes these injuries can lead to permanent facial weakness. In some cases, a surgical procedure may be performed to repair the nerve and associated muscle damage.

A tumor, abscess, viral infection, nerve disease or inflammatory disease can also damage the cranial nerve 7.These conditions can be treated and nerve function can be restored with treatment.

Complications of facial nerve damage can include difficulty eating. Also, as problems with cranial nerve 7 can affect a person's ability to blink, damage to theconjunctiva(the surface of the white part of the eye) orto horny(the surface of the colored part of the eye and the pupil).

These problems require attention such as eye patches to protect the eye from drying out and damage orswallowing therapyto help chew and eat safely.

Rehabilitation to improve facial nerve function after disability or injury may include physical therapy or electromyographic feedback techniques. In this process, electrical impulses from the facial muscles are measured and displayed, and the person learns what stimulates movement.

When to consult a healthcare professional

If you develop any symptoms of cranial nerve 7 involvement, it is important to seek medical attention immediately.

Symptoms include:

  • Drooping eyelid or decreased ability to open the eye
  • Inability to completely close the eye.
  • Flat or droopy appearance of any part of the face, on one side or both sides
  • a crooked smile
  • Problems speaking, chewing or swallowing
  • Problems moving the tongue

These symptoms could be caused by a health issue related to cranial nerve 7 or a condition that affects the brain, such as a stroke (blocked blood flow or bleeding in the brain) or a tumor.


Cranial nerve 7 controls movement of the face and also plays a role in sensation behind the ear and in the production of tears and saliva. The most common condition that affects cranial nerve 7 is Bell's palsy, a distressing condition that is not harmful.

However, there are many other conditions that can affect the seventh cranial nerve, and Bell's palsy is usually a diagnosis of exclusion, meaning that other causes of seventh cranial nerve weakness usually need to be ruled out before the diagnosis of palsy is made. done. . Complications of 7 cranial nerve problems can include corneal damage and difficulty eating.

A Word from Verywell

If you have a condition that affects cranial nerve 7 function, it is important to seek medical attention. It can be stressful not being able to move the muscles in your face the way you want to, and distressing to see your face crooked.

Facial nerve weakness is more than just a cosmetic concern: it can cause eye damage or be a choking hazard. Most problems with the 7 cranial nerves are treatable. As you recover, it's important to maintain physical therapy so that you can regain as much control of your facial movements as possible.

Common questions

  • What happens if cranial nerve 7 is damaged?

    If this nerve is damaged, you will develop weakness on one side of your face. This can cause problems opening or closing the eyelid, sagging cheeks, slurred speech, or a crooked smile.

  • How is cranial nerve 7 tested?

    This nerve is tested with a physical exam. Your doctor may ask you to blink, open your eyes wide, smile, purse your lips, and raise your eyebrows. In some situations, you may also haveelectromyography (EMG)or a nerve conduction study (NCV) to assess muscle and nerve function.

  • Can cranial nerve 7 be fixed?

    Some surgical procedures can repair this nerve or transplant a nerve. This may be considered if the nerve is injured. Illnesses that affect the 7th cranial nerve, such as infection or inflammation, are usually treated with medication, not surgery.

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  1. Freed B, Coker C, Steele R, Marolt C, Motzko M, Creamer BA, Dennis JF.Communicating branches of the facial nerve: descriptions and clinical considerations.J Cosmetic Surgery. February 11, 2022: sjac029. doi:10.1093/asj/sjac029

  2. Machetanz K , Grimm F , Schäfer R , Trakolis L , Hurth H , Haas P , Gharabaghi ​​A , Tatagiba M , Naros G .Design and evaluation of a personalized electromyographic biofeedback system for facial rehabilitation.frontal neuroscience.2022;16:666173. doi:10.3389/fnins.2022.666173

  3. Young TMIT, Joseph ANM, Misron K.A review of delayed facial nerve paresis as a complication after total endoscopic ear surgery..J Int Adv Otol. 2021;17(6):570-573. doi:10.5152/iao.2021.21189

What to know about cranial nerve 7 (facial nerve) (2)

ForDra. Heidi Moawad
Heidi Moawad is a neurologist and an expert in the field of brain health and neurological disorders. doctor Moawad regularly writes and edits health and career content for medical books and journals.

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