The 12 Cranial Nerves. Edited by Sterling Precision Nelson

Transcription

1 The 12 Cranial Nerves Edited by Sterling Precision Nelson

2 Cranial Nerve I: Olfactory Nerve Type of Nerve: Sensory Function of Nerve: Sense of Smell Brief description: The Olfactory Nerve is the first of the 12 pairs of cranial nerves in the brain. It s a sensory nerve, in charge of transmitting olfactory stimuli from the nose to the brain, Its actual origin is given by the cells of the olfactory bulb and is the shortest cranial pair of all of the pairs in the brain. Important side note: Damaged olfactory nerve cells can regenerate, but don t always reconnect properly in the brain. Dysnomia - Parosmia Dysnomia - Phantosmia Hyposmia Distortion of smelling that refers to the perception of the smell. Distortion of smelling that refers to a smell not present. A decreased ability to smell. No specific cure available, but symptoms lessen over time, in some patients it may take years. Can recover easily if it from sickness however rinsing out the sinus with saline solution will help treat the problem. there's no known cure or treatment for congenital anosmia. Anosmia A total inability to smell. there's no known cure or treatment for congenital anosmia.

3 Cranial Nerve II: Optical Type of Nerve: Sensory Function of Nerve: Vision Brief description: The Optical cranial pair is the second of the 12 pairs of cranial nerves and it is responsible for conducting visual stimuli from the eye to the brain. It is made of axons from the ganglion cells of the retina, that take the information of the photoreceptors to the brain, where later it will be integrated and interpreted and It emerges in the diencephalon. Hereditary Optic Neuropathies Ischemic Optic Neuropathy Optic Neuritis Papilledema Toxic Amblyopia Vision loss, Nystagmus hearing loss and possible trouble distinguishing shades of blue and yellow colors that they see. Vision loss, Giant cell arteritis, blockage in arteries. Multiple sclerosis, loss of vision. Disturbances in vision, headache, vomiting, increased brain pressure. Vision deteriorating, nutritional deficiency. No effective treatment, however limiting tobacco and alcohol slow the rate of the vision loss, magnifiers and vision aids help as well. Controlling blood pressure and diabetes, High doses of corticosteroids by mouth or vein. Corticosteroid, relief of pressure if tumor is present, magnifiers and vision aids. Corticosteroid, surgery or radiation therapy, weight loss and a diuretic, if infected can be treated by antibiotics. Avoid alcohol and other drugs. If lead is the cause use chelating drugs, if ethylene glycol or methanol poisoning then hemodialysis and fomeziple.

4 Cranial Nerve III: Oculomotor Type of Nerve: Motor Function of Nerve: Raise eyelids, move eyes, regulate the size of pupils, focus of lenses. Brief description: The Oculomotor cranial nerve is also known as the common ocular motor nerve. It is the third of the 12 pairs of cranial nerves. It controls eye movement and is also responsible for pupil size and It originates in the midbrain. Oculomotor Nerve Palsy Nystagmus Strabismus Diplopia and Ptosis, misalignment of eyes. Involuntary eye movement, reduced vision and depth perceptions, affects balance and coordination. Misaligned eyes, Esotropia and exotropia, double vision. No treatment, usually requires surgery. Eyeglasses and contact lenses, surgery can help. Magnifying glasses and increased lightning can arise improvement in vision as well. Optical, medical or Surgical are required depending on age.

5 Cranial Nerve IV: Trochlear Type of Nerve: Motor Function of Nerve: Eye movements, proprioception Brief description: The Trochlear nerve has a motor and somatic functions that are connected to the superior oblique muscle of the eye, being able to make the eyeballs move and rotate. Its nucleus also originates in the mesencephalon as well as the oculomotor nerve and is the fourth of the 12 pairs of cranial nerves. Unique aspects: Smallest number of axons. Greatest intracranial length. Only cranial nerve that exits from the dorsal aspect of the brainstem. Innervates a muscle on the opposite side of its origin. Trochlear Nerve Palsy Double images, limited eye movement, computed tomography. Eye exercises, prism glasses, usually resolves itself over time.

6 Cranial Nerve V: Trigeminal Type of Nerve: Mixed Function of Nerve: Sensations of the head and face, chewing movements, and muscle sense. Brief description: The Trigeminal is a mixed cranial nerve (sensitive, sensory and motor), being the largest of all cranial nerves, it is the fifth of the 12 pairs of cranial nerves. Its function is to carry sensitive information to the face, to convey information for the chewing process. The sensory fibers convey sensations of touch, pain, and temperature from the front of the head including the mouth and also from the meninges. Important side note: The anatomy of the Trigeminal nerve is used for portraying the Wallenberg Syndrome or Lateral Medullary Syndrome, in this syndrome a stroke causes a loss of pain-temperature sensation from one side of the face and the other side of the body. Trigeminal Neuralgia Extreme pain triggers from small things like eating or even feeling a breeze and smiling. Acupuncture, biofeedback, chiropractic, and vitamin or nutritional therapy may work, surgery is recommended.

7 Cranial Nerve VI: Abducens Type of Nerve: Motor Function of Nerve: Produce movements of the eyes Brief description: The abducens is also known as the external ocular motor cranial nerve and it is the sixth of the 12 pairs of cranial nerves. It is a cranial motor pair, responsible for transmitting the motor stimuli to the external rectus muscle of the eye and therefore allowing the eye to move to the opposite side from where we have the nose. Important side note: 15-40% of people with tuberculosis have some resulting cranial nerve deficit, the Abducens nerve is the most commonly affected cranial nerve in immunocompetent people with tuberculosis. Sixth Nerve Palsy Double vision, vision impairment, poor eye alignment, strabismus. Treatment is unnecessary and sixth nerve palsy improves in time.

8 Cranial Nerve VIII: Facial or Intermediate Type of Nerve: Mixed Function of Nerve: Facial expressions, secretion of saliva, taste. Brief description: This is another mixed cranial pair since it consists of several nerve fibers that perform different functions, like ordering the muscles of the face to create facial expressions and also send signals to the salivary and lacrimal glands. On the other hand, it collects taste information through the tongue. It is the seventh of the 12 pairs of cranial nerves. Bell s Palsy Pain behind their ear 1-2 propr to noticing weakness, sounds louder than normal, one side of face paralyzed. eye patching and lubrication, lubricating drops for the eye as well as eye ointment should be used at night.

9 Cranial Nerve VIII: Vestibulocochlear Type of Nerve: Sensory Function of Nerve: Balance or equilibrium sense. Hearing. Brief description: It is a sensory cranial nerve. It is also known as the auditory and vestibular nerve, thus forming vestibulocochlear. He is responsible for balance and orientation in space and auditory function. It is the eighth of the 12 pairs of cranial nerves. Important side note: Neurofibromatosis Type II Complete lost of hearing and loss of balance. Surgery of the removal of the acoustic neuroma. Vestibular Neuronitis Dizziness and vertigo. Will treat itself over time, avoid becoming dehydrated.

10 Cranial Nerve IX: Glossopharyngeal Type of Nerve: Mixed Function of Nerve: Taste and other sensations of tongue, swallowing, secretion of saliva, aid in reflex control of blood pressure and respiration. Brief description: It is a nerve whose influence lies in the tongue and pharynx. It collects information from the taste buds (tongue) and sensory information from the pharynx. It leads orders to the salivary gland and various neck muscles that help with swallowing. It also monitors blood pressure. It is the ninth of the 12 pairs of cranial nerves. Important side note: Glossopharyngeal neuralgia Brief excruciating pain, can be triggered from chewing, swallowing, talking, yawning, coughing or sneezing. Pain can last several minutes. Surgery mainly named microvascular decompression, taking Anticonvulsants may help.

11 Cranial Nerve X: Vagus Type of Nerve: Mixed Function of Nerve: Transmit impulses to muscles associated with speech, swallowing, the heart, smooth muscles of visceral organs in the thorax, and abdomen. Brief description: This nerve is also known as pneumogastric. It emerges from the medulla oblongata and supplies nerves to the pharynx, esophagus, larynx, trachea, bronchi, heart, stomach and liver. Like the previous nerve, it influences the action of swallowing but also in sending and transmitting signals to our autonomous system, to help the regulate activation and control stress levels or send signals directly to our sympathetic system. It is the tenth of the 12 pairs of cranial nerves. Gastroparesis Slow or no movement of food from the stomach to the small intestine. Treatment of gastroparesis includes diet, medication, and devices or procedures that facilitate emptying of the stomach.

12 Cranial Nerve XI: Accessory Type of Nerve: Motor Function of Nerve: Turning movements of the head, movements of the shoulder and viscera, voice production Brief description: This cranial pair is named the spinal nerve. It is a motor nerve and could be understood as one of the most pure. It governs movements of the head and shoulders by supplying the sternocleidomastoid and trapezius muscles in the (anterior and posterior) regions of the neck. The spinal nerve also allows us to throw our heads back. Thus, we would say that it intervenes in the movements of the head and the shoulders. It is the eleventh of the 12 pairs of cranial nerves. Accessory Nerve Disorder Partial paralysis, asymmetric neckline, drooping shoulder. Intraoperative procedures, postoperative procedures or an Eden-Lange procedure.

13 Cranial Nerve XII: Hypoglossal Type of Nerve: Motor Function of Nerve: Tongue movements Brief description: And last but not least the Hypoglossal cranial nerve, this is a motor nerve which, like the vagus and glossopharyngeal, is involved in tongue muscles, swallowing and speech. It is the final and twelfth of the 12 pairs of cranial nerves. Hypoglossal Nerve Disorder Tongue becomes weak, atrophies. Difficulty speaking, Chewing and Swallowing. Subtle twitches. Treatment depends on the cause at hand as their can be a few reasons.

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