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What is the facial nerve (CN VII)?
Jun 23, 2024 · The facial nerve, CN VII, is the seventh paired cranial nerve. In this article, we shall look at the anatomical course of the nerve, and the motor, sensory and parasympathetic functions of its terminal branches.
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Oct 30, 2023 · The seventh cranial nerve (CN VII), the facial nerve, is responsible for providing motor innervation to these facial muscles, enabling you to smile or frown. In addition to motor fibers, this multitasking nerve also contains sensory and parasympathetic components.
- Medical Content
- 29 min
- Overview
- Location of the cranial nerves
- What conditions and disorders affect the cranial nerves?
- Common signs and symptoms
- Cranial nerve function
- How can I keep my cranial nerves healthy?
- Cranial nerve diagram
- Takeaway
Cranial nerves are pairs of nerves that connect your brain to different parts of your head, neck, and trunk. Each nerve has a corresponding roman numeral between i and xii.
Your cranial nerves are pairs of nerves that connect your brain to different parts of your head, neck, and trunk. There are 12 of them, each named for its function or structure.
Their functions are usually categorized as being either sensory or motor. Sensory nerves involve your senses, such as smell, hearing, and touch. Motor nerves control the movement and function of muscles or glands.
Keep reading to learn more about each of the 12 cranial nerves and how they function.
The cranial nerves are located within the skull, on the underside of the brain. They begin in the nuclei of the brain and travel different paths to help control your senses and movement.
Each nerve has a corresponding Roman numeral between I and XII. This is based on their location from front to back. For example, your olfactory nerve is closest to the front of your head, so it’s designated as I.
Conditions and disorders of the cranial nerves can affect processes that involve vision, smell, hearing, speaking, and balance. They can also change the way you perceive sensation on the face and prevent or alter the movement of the head, eyes, neck, shoulders, throat, and tongue.
Cranial nerve palsy affects a motor nerve — one that controls movement.
If a sensory nerve is affected, it can cause pain or reduced sensation.
Conditions and disorders that affect the cranial nerves can include:
•Third nerve palsy. This disorder can cause a closed or partially closed eyelid, an enlarged pupil, and the movement of the eye outward and downward.
•Trigeminal neuralgia. Trigeminal neuralgia is a disorder of the fifth cranial nerve and typically causes pain on one side of the face.
Disorders affecting the cranial nerve can cause different symptoms, depending on which nerve is affected.
If you experience pain in your face, a change in your ability to alter the movement of your head or eye, or changes in sensation relating to vision, hearing, smell, balance, or speaking, you may have a cranial nerve disorder.
Symptoms of cranial nerve damage can include:
•pain in the face, tongue, head, or neck
•inability to focus the eye
•an eye that drifts to one side or downward
I. Olfactory nerve
The olfactory nerve sends sensory information to your brain about smells that you encounter. When you inhale molecules with a scent, known as aromatic molecules, they dissolve in a moist lining at the roof of your nasal cavity. This lining is called the olfactory epithelium. It stimulates receptors that generate nerve impulses that move to your olfactory bulb. Your olfactory bulb is an oval-shaped structure that contains specialized groups of nerve cells. From the olfactory bulb, nerves pass into your olfactory tract, which is located below the frontal lobe of your brain. Nerve signals are then sent to areas of your brain concerned with memory and recognition of smells.
II. Optic nerve
The optic nerve is the sensory nerve that involves vision. When light enters your eye, it comes into contact with special receptors in your retina called rods and cones. Rods are found in large numbers and are highly sensitive to light. They’re more specialized for black and white or night vision. Cones are present in smaller numbers. They have a lower light sensitivity than rods and are more involved with color vision. The information received by your rods and cones is sent from your retina to your optic nerve. Once inside your skull, both of your optic nerves meet to form something called the optic chiasm. At the optic chiasm, nerve fibers from half of each retina form two separate optic tracts. Through each optic tract, the nerve impulses eventually reach your visual cortex, which then processes the information. Your visual cortex is located in the back part of your brain.
III. Oculomotor nerve
The oculomotor nerve has two different motor functions: muscle function and pupil response. •Muscle function. Your oculomotor nerve provides motor function to four of the six muscles around your eyes. These muscles help your eyes move and focus on objects. •Pupil response. It also helps to control the size of your pupil as it responds to light. This nerve originates in the front part of your midbrain, which is a part of your brainstem. It moves forward from that area until it reaches the area of your eye sockets.
You can help keep your cranial nerves healthy by following practices that keep your body, cardiovascular system, and central nervous system healthy.
According to the National Institute of Neurological Disorders and Stroke (NINDS), certain practices may reduce your risk for a stroke or cardiovascular disease. These can include the following:
•getting about 7 to 9 hours of quality sleep each night
•not smoking, or if you smoke, quitting smoking if possible
•treating diabetes, if you have it
•treating high blood pressure, if you have it
Explore this interactive 3D diagram below to learn more about the 12 cranial nerves.
Your brain has 12 cranial nerves that are involved with your sensory, motor, and autonomic functions. They’re located inside of your skull on the underside of the brain. They’re numbered according to their location.
Jul 24, 2023 · The facial nerve is the seventh cranial nerve (CN VII). It arises from the brain stem and extends posteriorly to the abducens nerve and anteriorly to the vestibulocochlear nerve.
- Dominika Dulak, Imama A. Naqvi
- Gdansk Medical University, Temple University
- 2018
- 2023/07/24
Your facial nerve, also known as cranial nerve 7 and CN VII, is a nerve in your head that sends signals from your brain to parts of your face and vice versa. You have two facial nerves, one on each side of your head.
May 23, 2023 · The facial nerve is the seventh cranial nerve. It contains the motor, sensory, and parasympathetic (secretomotor) nerve fibers, which provide innervation to many areas of the head and neck region. The facial nerve is comprised of three nuclei:
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue.
