Abducens Nerve
Abducens Nerve Diseases
Abducens Nerve Injury
Horner Syndrome
Cavernous Sinus
Diplopia
Petrous Bone
Trochlear Nerve
Cranial Nerve Diseases
Eye Pain
Ophthalmoplegia
Oculomotor Nerve
Oculomotor Muscles
Cranial Nerve Neoplasms
Skull Fracture, Basilar
Oculomotor Nerve Diseases
Trigeminal Nerve
Paralysis
Duane Retraction Syndrome
Mucocele
Electronystagmography
Nerve Compression Syndromes
Dura Mater
Cranial Fossa, Posterior
Skull Base
Turtles
Sciatic Nerve
Neurilemmoma
Peripheral Nerves
Paresis
Cranial Nerves
Brain Stem
Optic Nerve
Meningioma
Nerve Fibers
Magnetic Resonance Imaging
Properties of conditioned abducens nerve responses in a highly reduced in vitro brain stem preparation from the turtle. (1/125)
Previous work suggested that the cerebellum and red nucleus are not necessary for the acquisition, extinction, and reacquistion of the in vitro classically conditioned abducens nerve response in the turtle. These findings are extended in the present study by obtaining conditioned responses (CRs) in preparations that received a partial ablation of the brain stem circuitry. In addition to removing all tissue rostral to and including the midbrain and cerebellum, a transection was made just caudal to the emergence of the IXth nerve. Such ablations result in a 4-mm-thick section of brain stem tissue that functionally eliminates the sustained component of the unconditioned response (UR) while leaving only a phasic component. We refer to this region of brain stem tissue caudal to the IXth nerve as the "caudal premotor blink region." Neural discharge was recorded from the abducens nerve following a single shock unconditioned stimulus (US) applied to the ipsilateral trigeminal nerve. When the US was paired with a conditioned stimulus (CS) applied to the posterior eighth, or auditory, nerve using a delay conditioning paradigm, a positive slope of CR acquisition was recorded in the abducens nerve, and CR extinction was recorded when the stimuli were alternated. Resumption of paired stimuli resulted in reacquisition. Quantitative analysis of the CRs in preparations in which the caudal premotor blink region had been removed and those with cerebellar/red nucleus lesions showed that both types of preparations had abnormally short latency CR onsets compared with preparations in which these regions were intact. Preparations with brain stem transections had significantly earlier CR offsets as more CRs terminated as short bursts when compared with intact or cerebellar lesioned preparations. These data suggest that a highly reduced in vitro brain stem preparation from the turtle can be classically conditioned. Furthermore, the caudal brain stem is not a site of acquisition in this reduced preparation, but it contributes to the sustained activity of both the UR and CR. Finally, the unusually short CR onset latencies following lesions to the cerebellum are not further exacerbated by removal of the caudal brain stem. These studies suggest that convergence of CS and US synaptic inputs onto the abducens nerve reflex circuitry may underlie acquisition in this reduced preparation, but that mechanisms that control learned CR timing arise from the cerebellorubral system. (+info)Discharge profiles of abducens, accessory abducens, and orbicularis oculi motoneurons during reflex and conditioned blinks in alert cats. (2/125)
The discharge profiles of identified abducens, accessory abducens, and orbicularis oculi motoneurons have been recorded extra- and intracellularly in alert behaving cats during spontaneous, reflexively evoked, and classically conditioned eyelid responses. The movement of the upper lid and the electromyographic activity of the orbicularis oculi muscle also were recorded. Animals were conditioned by short, weak air puffs or 350-ms tones as conditioned stimuli (CS) and long, strong air puffs as unconditioned stimulus (US) using both trace and delayed conditioning paradigms. Motoneurons were identified by antidromic activation from their respective cranial nerves. Orbicularis oculi and accessory abducens motoneurons fired an early, double burst of action potentials (at 4-6 and 10-16 ms) in response to air puffs or to the electrical stimulation of the supraorbital nerve. Orbicularis oculi, but not accessory abducens, motoneurons fired in response to flash and tone presentations. Only 10-15% of recorded abducens motoneurons fired a late, weak burst after air puff, supraorbital nerve, and flash stimulations. Spontaneous fasciculations of the orbicularis oculi muscle and the activity of single orbicularis oculi motoneurons that generated them also were recorded. The activation of orbicularis oculi motoneurons during the acquisition of classically conditioned eyelid responses happened in a gradual, sequential manner. Initially, some putative excitatory synaptic potentials were observed in the time window corresponding to the CS-US interval; by the second to the fourth conditioning session, some isolated action potentials appeared that increased in number until some small movements were noticed in eyelid position traces. No accessory abducens motoneuron fired and no abducens motoneuron modified their discharge rate for conditioned eyelid responses. The firing of orbicularis oculi motoneurons was related linearly to lid velocity during reflex blinks but to lid position during conditioned responses, a fact indicating the different neural origin and coding of both types of motor commands. The power spectra of both reflex and conditioned lid responses showed a dominant peak at approximately 20 Hz. The wavy appearance of both reflex and conditioned eyelid responses was clearly the result of the high phasic activity of orbicularis oculi motor units. Orbicularis oculi motoneuron membrane potentials oscillated at approximately 20 Hz after supraorbital nerve stimulation and during other reflex and conditioned eyelid movements. The oscillation seemed to be the result of both intrinsic (spike afterhyperpolarization lasting approximately 50 ms, and late depolarizations) and extrinsic properties of the motoneuronal pool and of the circuits involved in eye blinks. (+info)Stereotactic radiosurgery for cavernous sinus cavernous hemangioma--case report. (3/125)
A 40-year-old female presented with cavernous sinus cavernous hemangioma manifesting as left abducens and trigeminal nerve pareses. Magnetic resonance imaging revealed a left cavernous sinus tumor. The tumor was partially removed. Histological examination of the specimen confirmed cavernous hemangioma. Radiosurgery was performed using the gamma knife. The tumor markedly decreased in size after radiosurgery and morbidity was avoided. Cavernous sinus cavernous hemangiomas may be difficult to treat surgically due to intraoperative bleeding and cranial nerve injury. Stereotactic radiosurgery can be used either as an adjunct treatment to craniotomy, or as the primary treatment for small cavernous sinus cavernous hemangioma. (+info)Neuro-Behcet's disease presenting with isolated unilateral lateral rectus muscle palsy. (4/125)
The authors present the clinical findings of a 30-year-old female and a 29-year-old male who both had isolated unilateral lateral rectus muscle palsy in neuro-Behcet's disease. The clinical feature related to isolated abduscens nerve palsy was identified by CT, systemic assessment and extraocular examination. These patients' constellation of findings appear to be unique: it does not follow any previously reported pattern of ocular manifestations of neuro-Behcet's disease. (+info)Quantitative analysis of abducens neuron discharge dynamics during saccadic and slow eye movements. (5/125)
The mechanics of the eyeball and its surrounding tissues, which together form the oculomotor plant, have been shown to be the same for smooth pursuit and saccadic eye movements. Hence it was postulated that similar signals would be carried by motoneurons during slow and rapid eye movements. In the present study, we directly addressed this proposal by determining which eye movement-based models best describe the discharge dynamics of primate abducens neurons during a variety of eye movement behaviors. We first characterized abducens neuron spike trains, as has been classically done, during fixation and sinusoidal smooth pursuit. We then systematically analyzed the discharge dynamics of abducens neurons during and following saccades, during step-ramp pursuit and during high velocity slow-phase vestibular nystagmus. We found that the commonly utilized first-order description of abducens neuron firing rates (FR = b + kE + r, where FR is firing rate, E and are eye position and velocity, respectively, and b, k, and r are constants) provided an adequate model of neuronal activity during saccades, smooth pursuit, and slow phase vestibular nystagmus. However, the use of a second-order model, which included an exponentially decaying term or "slide" (FR = b + kE + r + uE - c), notably improved our ability to describe neuronal activity when the eye was moving and also enabled us to model abducens neuron discharges during the postsaccadic interval. We also found that, for a given model, a single set of parameters could not be used to describe neuronal firing rates during both slow and rapid eye movements. Specifically, the eye velocity and position coefficients (r and k in the above models, respectively) consistently decreased as a function of the mean (and peak) eye velocity that was generated. In contrast, the bias (b, firing rate when looking straight ahead) invariably increased with eye velocity. Although these trends are likely to reflect, in part, nonlinearities that are intrinsic to the extraocular muscles, we propose that these results can also be explained by considering the time-varying resistance to movement that is generated by the antagonist muscle. We conclude that to create realistic and meaningful models of the neural control of horizontal eye movements, it is essential to consider the activation of the antagonist, as well as agonist motoneuron pools. (+info)Apparent dissociation between saccadic eye movements and the firing patterns of premotor neurons and motoneurons. (6/125)
Saccadic eye movements result from high-frequency bursts of activity in ocular motoneurons. This phasic activity originates in premotor burst neurons. When the head is restrained, the number of action potentials in the bursts of burst neurons and motoneurons increases linearly with eye movement amplitude. However, when the head is unrestrained, the number of action potentials now increase as a function of the change in the direction of the line of sight during eye movements of relatively similar amplitudes. These data suggest an apparent uncoupling of premotor neuron and motoneuron activity from the resultant eye movement. (+info)Early components of the human vestibulo-ocular response to head rotation: latency and gain. (7/125)
To characterize vestibulo-ocular reflex (VOR) properties in the time window in which contributions by other systems are minimal, eye movements during the first 50-100 ms after the start of transient angular head accelerations ( approximately 1000 degrees /s(2)) imposed by a torque helmet were analyzed in normal human subjects. Orientations of the head and both eyes were recorded with magnetic search coils (resolution, approximately 1 min arc; 1000 samples/s). Typically, the first response to a head perturbation was an anti-compensatory eye movement with zero latency, peak-velocity of several degrees per second, and peak excursion of several tenths of a degree. This was interpreted as a passive mechanical response to linear acceleration of the orbital tissues caused by eccentric rotation of the eye. The response was modeled as a damped oscillation (approximately 13 Hz) of the orbital contents, approaching a constant eye deviation for a sustained linear acceleration. The subsequent compensatory eye movements showed (like the head movements) a linear increase in velocity, which allowed estimates of latency and gain with linear regressions. After appropriate accounting for the preceding passive eye movements, average VOR latency (for pooled eyes, directions, and subjects) was calculated as 8.6 ms. Paired comparisons between the two eyes revealed that the latency for the eye contralateral to the direction of head rotation was, on average, 1.3 ms shorter than for the ipsilateral eye. This highly significant average inter-ocular difference was attributed to the additional internuclear abducens neuron in the pathway to the ipsilateral eye. Average acceleration gain (ratio between slopes of eye and head velocities) over the first 40-50 ms was approximately 1.1. Instantaneous velocity gain, calculated as Veye(t)/Vhead(t-latency), showed a gradual build-up converging toward unity (often after a slight overshoot). Instantaneous acceleration gain also converged toward unity but showed a much steeper build-up and larger oscillations. This behavior of acceleration and velocity gain could be accounted for by modeling the eye movements as the sum of the passive response to the linear acceleration and the active rotational VOR. Due to the latency and the anticompensatory component, gaze stabilization was never complete. The influence of visual targets was limited. The initial VOR was identical with a distant target (continuously visible or interrupted) and in complete darkness. A near visual target caused VOR gain to rise to a higher level, but the time after which the difference between far and near targets emerged varied between individuals. (+info)Expansion of afferent vestibular signals after the section of one of the vestibular nerve branches. (8/125)
The anterior branch of N. VIII was sectioned in adult frogs. Two months later the brain was isolated to record in vitro responses in the vestibular nuclei and from the abducens nerves following electric stimulation of the anterior branch of N. VIII or of the posterior canal nerve. Extra- and intracellularly recorded responses from the intact and operated side were compared with responses from controls. Major changes were detected on the operated side: the amplitudes of posterior canal nerve evoked field potentials were enlarged, the number of vestibular neurons with a monosynaptic input from the posterior canal nerve had increased, and posterior canal nerve stimulation recruited stronger abducens nerve responses on the intact side than vice versa. Changes in the convergence pattern of vestibular nerve afferent inputs on the operated side strongly suggest the expansion of posterior canal-related afferent inputs onto part of those vestibular neurons that were deprived of their afferent vestibular input. As a mechanism we suggest reactive synaptogenesis between intact posterior canal afferent fibers and vestibularly deprived second-order vestibular neurons. (+info)The abducens nerve, also known as the sixth cranial nerve (CN VI), is a motor nerve that controls the lateral rectus muscle of the eye. This muscle is responsible for moving the eye away from the midline (towards the temple) and enables the eyes to look towards the side while keeping them aligned. Any damage or dysfunction of the abducens nerve can result in strabismus, where the eyes are misaligned and point in different directions, specifically an adduction deficit, also known as abducens palsy or sixth nerve palsy.
The abducens nerve, also known as the sixth cranial nerve, is responsible for controlling the lateral rectus muscle of the eye, which enables the eye to move outward. Abducens nerve diseases refer to conditions that affect this nerve and can result in various symptoms, primarily affecting eye movement.
Here are some medical definitions related to abducens nerve diseases:
1. Abducens Nerve Palsy: A condition characterized by weakness or paralysis of the abducens nerve, causing difficulty in moving the affected eye outward. This results in double vision (diplopia), especially when gazing towards the side of the weakened nerve. Abducens nerve palsy can be congenital, acquired, or caused by various factors such as trauma, tumors, aneurysms, infections, or diseases like diabetes and multiple sclerosis.
2. Sixth Nerve Palsy: Another term for abducens nerve palsy, referring to the weakness or paralysis of the sixth cranial nerve.
3. Internuclear Ophthalmoplegia (INO): A neurological condition affecting eye movement, often caused by a lesion in the medial longitudinal fasciculus (MLF), a bundle of nerve fibers that connects the abducens nucleus with the oculomotor nucleus. INO results in impaired adduction (inward movement) of the eye on the side of the lesion and nystagmus (involuntary eye movements) of the abducting eye on the opposite side when attempting to look towards the side of the lesion.
4. One-and-a-Half Syndrome: A rare neurological condition characterized by a combination of INO and internuclear ophthalmoplegia with horizontal gaze palsy on the same side, caused by damage to both the abducens nerve and the paramedian pontine reticular formation (PPRF). This results in limited or no ability to move the eyes towards the side of the lesion and impaired adduction of the eye on the opposite side.
5. Brainstem Encephalitis: Inflammation of the brainstem, which can affect the abducens nerve and other cranial nerves, leading to various neurological symptoms such as diplopia (double vision), ataxia (loss of balance and coordination), and facial weakness. Brainstem encephalitis can be caused by infectious agents, autoimmune disorders, or paraneoplastic syndromes.
6. Multiple Sclerosis (MS): An autoimmune disorder characterized by inflammation and demyelination of the central nervous system, including the brainstem and optic nerves. MS can cause various neurological symptoms, such as diplopia, nystagmus, and INO, due to damage to the abducens nerve and other cranial nerves.
7. Wernicke's Encephalopathy: A neurological disorder caused by thiamine (vitamin B1) deficiency, often seen in alcoholics or individuals with malnutrition. Wernicke's encephalopathy can affect the brainstem and cause various symptoms such as diplopia, ataxia, confusion, and oculomotor abnormalities.
8. Pontine Glioma: A rare type of brain tumor that arises from the glial cells in the pons (a part of the brainstem). Pontine gliomas can cause various neurological symptoms such as diplopia, facial weakness, and difficulty swallowing due to their location in the brainstem.
9. Brainstem Cavernous Malformation: A benign vascular lesion that arises from the small blood vessels in the brainstem. Brainstem cavernous malformations can cause various neurological symptoms such as diplopia, ataxia, and facial weakness due to their location in the brainstem.
10. Pituitary Adenoma: A benign tumor that arises from the pituitary gland, located at the base of the brain. Large pituitary adenomas can compress the optic nerves and cause various visual symptoms such as diplopia, visual field defects, and decreased vision.
11. Craniopharyngioma: A benign tumor that arises from the remnants of the Rathke's pouch, a structure that gives rise to the anterior pituitary gland. Craniopharyngiomas can cause various neurological and endocrine symptoms such as diplopia, visual field defects, headaches, and hormonal imbalances due to their location near the optic nerves and pituitary gland.
12. Meningioma: A benign tumor that arises from the meninges, the protective covering of the brain and spinal cord. Meningiomas can cause various neurological symptoms such as diplopia, headaches, and seizures depending on their location in the brain or spinal cord.
13. Chordoma: A rare type of malignant tumor that arises from the remnants of the notochord, a structure that gives rise to the spine during embryonic development. Chordomas can cause various neurological and endocrine symptoms such as diplopia, visual field defects, headaches, and hormonal imbalances due to their location near the brainstem and spinal cord.
14. Metastatic Brain Tumors: Malignant tumors that spread from other parts of the body to the brain. Metastatic brain tumors can cause various neurological symptoms such as diplopia, headaches, seizures, and cognitive impairment depending on their location in the brain.
15. Other Rare Brain Tumors: There are many other rare types of brain tumors that can cause diplopia or other neurological symptoms, including gliomas, ependymomas, pineal region tumors, and others. These tumors require specialized diagnosis and treatment by neuro-oncologists and neurosurgeons with expertise in these rare conditions.
In summary, diplopia can be caused by various brain tumors, including pituitary adenomas, meningiomas, chordomas, metastatic brain tumors, and other rare types of tumors. It is important to seek medical attention promptly if you experience diplopia or other neurological symptoms, as early diagnosis and treatment can improve outcomes and quality of life.
The abducens nerve, also known as the sixth cranial nerve, is responsible for controlling the lateral rectus muscle of the eye, which allows for horizontal movement of the eye outwards. An injury to the abducens nerve can result in various symptoms related to eye movement and alignment.
Medical definition:
Abducens nerve injury refers to damage or trauma to the sixth cranial nerve, resulting in dysfunction of the lateral rectus muscle and subsequent impairment of horizontal gaze. The affected individual may experience difficulty in moving the eye outwards, double vision (diplopia), or a condition known as strabismus, where the eyes are misaligned and point in different directions. Abducens nerve injury can occur due to various reasons, such as head trauma, tumors, increased intracranial pressure, or neurological disorders like multiple sclerosis. Treatment typically involves addressing the underlying cause and may include surgical intervention, eye patching, or prism lenses to manage symptoms and improve visual function.
Horner syndrome, also known as Horner's syndrome or oculosympathetic palsy, is a neurological disorder characterized by the interruption of sympathetic nerve pathways that innervate the head and neck, leading to a constellation of signs affecting the eye and face on one side of the body.
The classic triad of symptoms includes:
1. Ptosis (drooping) of the upper eyelid: This is due to the weakness or paralysis of the levator palpebrae superioris muscle, which is responsible for elevating the eyelid.
2. Miosis (pupillary constriction): The affected pupil becomes smaller in size compared to the other side, and it may not react as robustly to light.
3. Anhydrosis (decreased sweating): There is reduced or absent sweating on the ipsilateral (same side) of the face, particularly around the forehead and upper eyelid.
Horner syndrome can be caused by various underlying conditions, such as brainstem stroke, tumors, trauma, or certain medical disorders affecting the sympathetic nervous system. The diagnosis typically involves a thorough clinical examination, pharmacological testing, and sometimes imaging studies to identify the underlying cause. Treatment is directed towards managing the underlying condition responsible for Horner syndrome.
The cavernous sinus is a venous structure located in the middle cranial fossa, which is a depression in the skull that houses several important nerves and blood vessels. The cavernous sinus is situated on either side of the sphenoid bone, near the base of the skull, and it contains several important structures:
* The internal carotid artery, which supplies oxygenated blood to the brain
* The abducens nerve (cranial nerve VI), which controls lateral movement of the eye
* The oculomotor nerve (cranial nerve III), which controls most of the muscles that move the eye
* The trochlear nerve (cranial nerve IV), which controls one of the muscles that moves the eye
* The ophthalmic and maxillary divisions of the trigeminal nerve (cranial nerve V), which transmit sensory information from the face and head
The cavernous sinus is an important structure because it serves as a conduit for several critical nerves and blood vessels. However, it is also vulnerable to various pathological conditions such as thrombosis (blood clots), infection, tumors, or aneurysms, which can lead to serious neurological deficits or even death.
Diplopia is a medical term that refers to the condition where a person sees two images of a single object. It is commonly known as double vision. This can occur due to various reasons, such as nerve damage or misalignment of the eyes. Diplopia can be temporary or chronic and can affect one or both eyes. If you're experiencing diplopia, it's essential to consult an eye care professional for proper evaluation and treatment.
The petrous bone is a part of the temporal bone, one of the 22 bones in the human skull. It is a thick and irregularly shaped bone located at the base of the skull and forms part of the ear and the cranial cavity. The petrous bone contains the cochlea, vestibule, and semicircular canals of the inner ear, which are responsible for hearing and balance. It also helps protect the brain from injury by forming part of the bony structure surrounding the brain.
The term "petrous" comes from the Latin word "petrosus," meaning "stony" or "rock-like," which describes the hard and dense nature of this bone. The petrous bone is one of the densest bones in the human body, making it highly resistant to fractures and other forms of damage.
In medical terminology, the term "petrous" may also be used to describe any structure that resembles a rock or is hard and dense, such as the petrous apex, which refers to the portion of the petrous bone that points towards the sphenoid bone.
The trochlear nerve, also known as the fourth cranial nerve (CN IV), is a nerve that originates in the midbrain and innervates the superior oblique muscle of the eye. This muscle helps with the downward and outward movement of the eye, playing a crucial role in controlling eye movements and maintaining binocular vision. The trochlear nerve's main function is to provide motor (efferent) innervation to the superior oblique muscle, enabling fine-tuning of eye movements during activities such as reading, writing, or driving. Damage to this nerve can result in vertical diplopia (double vision), strabismus (eye misalignment), and other visual impairments.
Cranial nerve diseases refer to conditions that affect the cranial nerves, which are a set of 12 pairs of nerves that originate from the brainstem and control various functions in the head and neck. These functions include vision, hearing, taste, smell, movement of the eyes and face, and sensation in the face.
Diseases of the cranial nerves can result from a variety of causes, including injury, infection, inflammation, tumors, or degenerative conditions. The specific symptoms that a person experiences will depend on which cranial nerve is affected and how severely it is damaged.
For example, damage to the optic nerve (cranial nerve II) can cause vision loss or visual disturbances, while damage to the facial nerve (cranial nerve VII) can result in weakness or paralysis of the face. Other common symptoms of cranial nerve diseases include pain, numbness, tingling, and hearing loss.
Treatment for cranial nerve diseases varies depending on the underlying cause and severity of the condition. In some cases, medication or surgery may be necessary to treat the underlying cause and relieve symptoms. Physical therapy or rehabilitation may also be recommended to help individuals regain function and improve their quality of life.
Eye pain is defined as discomfort or unpleasant sensations in the eye. It can be sharp, throbbing, stabbing, burning, or aching. The pain may occur in one or both eyes and can range from mild to severe. Eye pain can result from various causes, including infection, inflammation, injury, or irritation of the structures of the eye, such as the cornea, conjunctiva, sclera, or uvea. Other possible causes include migraines, optic neuritis, and glaucoma. It is essential to seek medical attention if experiencing sudden, severe, or persistent eye pain, as it can be a sign of a serious underlying condition that requires prompt treatment.
Ophthalmoplegia is a medical term that refers to the paralysis or weakness of the eye muscles, which can result in double vision (diplopia) or difficulty moving the eyes. It can be caused by various conditions, including nerve damage, muscle disorders, or neurological diseases such as myasthenia gravis or multiple sclerosis. Ophthalmoplegia can affect one or more eye muscles and can be partial or complete. Depending on the underlying cause, ophthalmoplegia may be treatable with medications, surgery, or other interventions.
The oculomotor nerve, also known as the third cranial nerve (CN III), is a motor nerve that originates from the midbrain. It controls the majority of the eye muscles, including the levator palpebrae superioris muscle that raises the upper eyelid, and the extraocular muscles that enable various movements of the eye such as looking upward, downward, inward, and outward. Additionally, it carries parasympathetic fibers responsible for pupillary constriction and accommodation (focusing on near objects). Damage to this nerve can result in various ocular motor disorders, including strabismus, ptosis, and pupillary abnormalities.
The oculomotor muscles are a group of extraocular muscles that control the movements of the eye. They include:
1. Superior rectus: This muscle is responsible for elevating the eye and helping with inward rotation (intorsion) when looking downwards.
2. Inferior rectus: It depresses the eye and helps with outward rotation (extorsion) when looking upwards.
3. Medial rectus: This muscle adducts, or moves, the eye towards the midline of the face.
4. Inferior oblique: The inferior oblique muscle intorts and elevates the eye.
5. Superior oblique: It extorts and depresses the eye.
These muscles work together to allow for smooth and precise movements of the eyes, enabling tasks such as tracking moving objects, reading, and maintaining visual fixation on a single point in space.
Cranial nerve neoplasms refer to abnormal growths or tumors that develop within or near the cranial nerves. These nerves are responsible for transmitting sensory and motor information between the brain and various parts of the head, neck, and trunk. There are 12 pairs of cranial nerves, each with a specific function and location in the skull.
Cranial nerve neoplasms can be benign or malignant and may arise from the nerve itself (schwannoma, neurofibroma) or from surrounding tissues that invade the nerve (meningioma, epidermoid cyst). The growth of these tumors can cause various symptoms depending on their size, location, and rate of growth. Common symptoms include:
* Facial weakness or numbness
* Double vision or other visual disturbances
* Hearing loss or tinnitus (ringing in the ears)
* Difficulty swallowing or speaking
* Loss of smell or taste
* Uncontrollable eye movements or drooping eyelids
Treatment for cranial nerve neoplasms depends on several factors, including the type, size, location, and extent of the tumor, as well as the patient's overall health. Treatment options may include surgery, radiation therapy, chemotherapy, or a combination of these approaches. Regular follow-up care is essential to monitor for recurrence or complications.
A basilar skull fracture is a type of skull fracture that involves the base of the skull. It is a serious and potentially life-threatening injury, as it can cause damage to the brainstem and cranial nerves. A basilar skull fracture may occur as a result of a severe head trauma, such as from a fall, car accident, or violent assault.
In a basilar skull fracture, the bones that form the base of the skull (the occipital bone, sphenoid bone, and temporal bones) are broken. This type of fracture can be difficult to diagnose on a routine skull X-ray, and may require further imaging studies such as a CT scan or MRI to confirm the diagnosis.
Symptoms of a basilar skull fracture may include:
* Battle's sign: a bruise behind the ear
* Raccoon eyes: bruising around the eyes
* Clear fluid leaking from the nose or ears (cerebrospinal fluid)
* Hearing loss
* Facial paralysis
* Difficulty swallowing
* Changes in level of consciousness
If you suspect that someone has a basilar skull fracture, it is important to seek medical attention immediately. This type of injury requires prompt treatment and close monitoring to prevent complications such as infection or brain swelling.
The oculomotor nerve, also known as the third cranial nerve (CN III), is responsible for controlling several important eye movements and functions. Oculomotor nerve diseases refer to conditions that affect this nerve and can lead to various symptoms related to eye movement and function. Here's a medical definition of oculomotor nerve diseases:
Oculomotor nerve diseases are a group of medical disorders characterized by the dysfunction or damage to the oculomotor nerve (CN III), resulting in impaired eye movements, abnormalities in pupillary response, and potential effects on eyelid position. These conditions can be congenital, acquired, or traumatic in nature and may lead to partial or complete paralysis of the nerve. Common oculomotor nerve diseases include oculomotor nerve palsy, third nerve ganglionopathies, and compressive oculomotor neuropathies caused by various pathologies such as aneurysms, tumors, or infections.
The trigeminal nerve, also known as the fifth cranial nerve or CNV, is a paired nerve that carries both sensory and motor information. It has three major branches: ophthalmic (V1), maxillary (V2), and mandibular (V3). The ophthalmic branch provides sensation to the forehead, eyes, and upper portion of the nose; the maxillary branch supplies sensation to the lower eyelid, cheek, nasal cavity, and upper lip; and the mandibular branch is responsible for sensation in the lower lip, chin, and parts of the oral cavity, as well as motor function to the muscles involved in chewing. The trigeminal nerve plays a crucial role in sensations of touch, pain, temperature, and pressure in the face and mouth, and it also contributes to biting, chewing, and swallowing functions.
Paralysis is a loss of muscle function in part or all of your body. It can be localized, affecting only one specific area, or generalized, impacting multiple areas or even the entire body. Paralysis often occurs when something goes wrong with the way messages pass between your brain and muscles. In most cases, paralysis is caused by damage to the nervous system, especially the spinal cord. Other causes include stroke, trauma, infections, and various neurological disorders.
It's important to note that paralysis doesn't always mean a total loss of movement or feeling. Sometimes, it may just cause weakness or numbness in the affected area. The severity and extent of paralysis depend on the underlying cause and the location of the damage in the nervous system.
Duane Retraction Syndrome (DRS) is a congenital eye movement disorder, characterized by limited abduction (lateral movement away from the nose) of the affected eye, and on attempted adduction (movement towards the nose), the eye retracts into the orbit and the lid narrows. It is often accompanied by other eye alignment or vision anomalies. The exact cause is not known, but it is believed to be a result of abnormal development of the cranial nerves that control eye movement during fetal development. DRS is usually idiopathic, but it can also be associated with other congenital anomalies. It is typically diagnosed in early childhood and managed with a combination of observation, prism glasses, and/or surgery, depending on the severity and impact on vision.
A mucocele is a mucus-containing cystic lesion that results from the accumulation of mucin within a damaged minor salivary gland duct or mucous gland. It is typically caused by trauma, injury, or blockage of the duct. Mucocele appears as a round, dome-shaped, fluid-filled swelling, which may be bluish or clear in color. They are most commonly found on the lower lip but can also occur on other areas of the oral cavity. Mucocele is generally painless unless it becomes secondarily infected; however, it can cause discomfort during speaking, chewing, or swallowing, and may affect aesthetics. Treatment usually involves surgical excision of the mucocele to prevent recurrence.
Eye movements, also known as ocular motility, refer to the voluntary or involuntary motion of the eyes that allows for visual exploration of our environment. There are several types of eye movements, including:
1. Saccades: rapid, ballistic movements that quickly shift the gaze from one point to another.
2. Pursuits: smooth, slow movements that allow the eyes to follow a moving object.
3. Vergences: coordinated movements of both eyes in opposite directions, usually in response to a three-dimensional stimulus.
4. Vestibulo-ocular reflex (VOR): automatic eye movements that help stabilize the gaze during head movement.
5. Optokinetic nystagmus (OKN): rhythmic eye movements that occur in response to large moving visual patterns, such as when looking out of a moving vehicle.
Abnormalities in eye movements can indicate neurological or ophthalmological disorders and are often assessed during clinical examinations.
Electronystagmography (ENG) is a medical test used to assess the function of the vestibular system, which is responsible for maintaining balance and eye movements. This test measures involuntary eye movements, called nystagmus, which can be indicative of various conditions affecting the inner ear or brainstem.
During the ENG test, electrodes are placed around the eyes to record eye movements while the patient undergoes a series of stimuli, such as changes in head position, visual stimuli, and caloric irrigations (where warm or cool water is introduced into the ear canal to stimulate the inner ear). The recorded data is then analyzed to evaluate the function of the vestibular system and identify any abnormalities.
ENG testing can help diagnose conditions such as vestibular neuritis, labyrinthitis, benign paroxysmal positional vertigo (BPPV), Meniere's disease, and other balance disorders. It is also used to assess the effectiveness of various treatments for these conditions.
Nerve compression syndromes refer to a group of conditions characterized by the pressure or irritation of a peripheral nerve, causing various symptoms such as pain, numbness, tingling, and weakness in the affected area. This compression can occur due to several reasons, including injury, repetitive motion, bone spurs, tumors, or swelling. Common examples of nerve compression syndromes include carpal tunnel syndrome, cubital tunnel syndrome, radial nerve compression, and ulnar nerve entrapment at the wrist or elbow. Treatment options may include physical therapy, splinting, medications, injections, or surgery, depending on the severity and underlying cause of the condition.
Dura Mater is the thickest and outermost of the three membranes (meninges) that cover the brain and spinal cord. It provides protection and support to these delicate structures. The other two layers are called the Arachnoid Mater and the Pia Mater, which are thinner and more delicate than the Dura Mater. Together, these three layers form a protective barrier around the central nervous system.
The posterior cranial fossa is a term used in anatomy to refer to the portion of the skull that forms the lower, back part of the cranial cavity. It is located between the occipital bone and the temporal bones, and it contains several important structures including the cerebellum, pons, medulla oblongata, and the lower cranial nerves (IX-XII). The posterior fossa also contains the foramen magnum, which is a large opening through which the spinal cord connects to the brainstem. This region of the skull is protected by the occipital bone, which forms the base of the skull and provides attachment for several neck muscles.
The skull base is the lower part of the skull that forms the floor of the cranial cavity and the roof of the facial skeleton. It is a complex anatomical region composed of several bones, including the frontal, sphenoid, temporal, occipital, and ethmoid bones. The skull base supports the brain and contains openings for blood vessels and nerves that travel between the brain and the face or neck. The skull base can be divided into three regions: the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa, which house different parts of the brain.
I'm sorry for any confusion, but "turtles" is not a medical term. It refers to the group of reptiles that have a shell and include various species such as tortoises and terrapins. If you have any medical concerns or questions, I would be happy to try to help with those!
The sciatic nerve is the largest and longest nerve in the human body, running from the lower back through the buttocks and down the legs to the feet. It is formed by the union of the ventral rami (branches) of the L4 to S3 spinal nerves. The sciatic nerve provides motor and sensory innervation to various muscles and skin areas in the lower limbs, including the hamstrings, calf muscles, and the sole of the foot. Sciatic nerve disorders or injuries can result in symptoms such as pain, numbness, tingling, or weakness in the lower back, hips, legs, and feet, known as sciatica.
A neurilemmoma, also known as schwannoma or peripheral nerve sheath tumor, is a benign, slow-growing tumor that arises from the Schwann cells, which produce the myelin sheath that surrounds and insulates peripheral nerves. These tumors can occur anywhere along the course of a peripheral nerve, but they most commonly affect the acoustic nerve (vestibulocochlear nerve), leading to a type of tumor called vestibular schwannoma or acoustic neuroma. Neurilemmomas are typically encapsulated and do not invade the surrounding tissue, although larger ones may cause pressure-related symptoms due to compression of nearby structures. Rarely, these tumors can undergo malignant transformation, leading to a condition called malignant peripheral nerve sheath tumor or neurofibrosarcoma.
Peripheral nerves are nerve fibers that transmit signals between the central nervous system (CNS, consisting of the brain and spinal cord) and the rest of the body. These nerves convey motor, sensory, and autonomic information, enabling us to move, feel, and respond to changes in our environment. They form a complex network that extends from the CNS to muscles, glands, skin, and internal organs, allowing for coordinated responses and functions throughout the body. Damage or injury to peripheral nerves can result in various neurological symptoms, such as numbness, weakness, or pain, depending on the type and severity of the damage.
Paresis is a medical term that refers to a partial loss of voluntary muscle function. It is often described as muscle weakness, and it can affect one or several parts of the body. Paresis can be caused by various conditions, including nerve damage, stroke, spinal cord injuries, multiple sclerosis, and infections like polio or botulism. The severity of paresis can range from mild to severe, depending on the underlying cause and the specific muscles involved. Treatment for paresis typically focuses on addressing the underlying condition causing it.
Cranial nerves are a set of twelve pairs of nerves that originate from the brainstem and skull, rather than the spinal cord. These nerves are responsible for transmitting sensory information (such as sight, smell, hearing, and taste) to the brain, as well as controlling various muscles in the head and neck (including those involved in chewing, swallowing, and eye movement). Each cranial nerve has a specific function and is named accordingly. For example, the optic nerve (cranial nerve II) transmits visual information from the eyes to the brain, while the vagus nerve (cranial nerve X) controls parasympathetic functions in the body such as heart rate and digestion.
The brainstem is the lower part of the brain that connects to the spinal cord. It consists of the midbrain, pons, and medulla oblongata. The brainstem controls many vital functions such as heart rate, breathing, and blood pressure. It also serves as a relay center for sensory and motor information between the cerebral cortex and the rest of the body. Additionally, several cranial nerves originate from the brainstem, including those that control eye movements, facial movements, and hearing.
The optic nerve, also known as the second cranial nerve, is the nerve that transmits visual information from the retina to the brain. It is composed of approximately one million nerve fibers that carry signals related to vision, such as light intensity and color, from the eye's photoreceptor cells (rods and cones) to the visual cortex in the brain. The optic nerve is responsible for carrying this visual information so that it can be processed and interpreted by the brain, allowing us to see and perceive our surroundings. Damage to the optic nerve can result in vision loss or impairment.
A meningioma is a type of slow-growing tumor that forms on the membranes (meninges) surrounding the brain and spinal cord. It's usually benign, meaning it doesn't spread to other parts of the body, but it can still cause serious problems if it grows and presses on nearby tissues.
Meningiomas most commonly occur in adults, and are more common in women than men. They can cause various symptoms depending on their location and size, including headaches, seizures, vision or hearing problems, memory loss, and changes in personality or behavior. In some cases, they may not cause any symptoms at all and are discovered only during imaging tests for other conditions.
Treatment options for meningiomas include monitoring with regular imaging scans, surgery to remove the tumor, and radiation therapy to shrink or kill the tumor cells. The best treatment approach depends on factors such as the size and location of the tumor, the patient's age and overall health, and their personal preferences.
Nerve fibers are specialized structures that constitute the long, slender processes (axons) of neurons (nerve cells). They are responsible for conducting electrical impulses, known as action potentials, away from the cell body and transmitting them to other neurons or effector organs such as muscles and glands. Nerve fibers are often surrounded by supportive cells called glial cells and are grouped together to form nerve bundles or nerves. These fibers can be myelinated (covered with a fatty insulating sheath called myelin) or unmyelinated, which influences the speed of impulse transmission.
Medical Definition:
Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.
Abducens nerve
Gorgonopsia
Sixth nerve palsy
Posterior clinoid processes
Idiopathic intracranial hypertension
Recurrent painful ophthalmoplegic neuropathy
Conjugate gaze palsy
Extraocular muscles
Dorello's canal
NKX 2-9
Motor neuron
Paul Julius Möbius
Clivus (anatomy)
Primo Dorello
Duane-radial ray syndrome
Cranial nerves
Lateral rectus muscle
Anesthesia for eye surgery
Abducens nucleus
Vestibulo-ocular reflex
Vestibulospinal tract
Fazio-Londe disease
Vergence
Pituitary adenoma
Smile surgery
Axial twist theory
Medial longitudinal fasciculus
Sense of balance
Gaze (physiology)
Synkinesis
Abducens nerve - Wikipedia
Abducens Nerve Palsy (Sixth Cranial Nerve Palsy): Background, Pathophysiology, Epidemiology
Absence of the abducens nerve in Duane syndrome verified by magnetic resonance imaging
Sixth Cranial (Abducens) Nerve Palsy - Neurologic Disorders - MSD Manual Professional Edition
Abducens Nerve Palsy
Cranial Nerve 6: Abducens Nerve
Abducens Nerve Injury | Profiles RNS
Abducens nerve (#14097) - Kenhub Image License Store
2-Minute Neuroscience: Abducens Nerve (Cranial Nerve VI)
Recurrence of systemic lupus erythematosus in a hemodialysis patient presenting as a unilateral abducens nerve palsy<...
Abducens nerve palsy (Radiopaedia 51069-56648 Axial T2 fat sat) - NC Commons
Abducens nerve palsy in a case under treatment with systemic interferon<...
Absence of the abducens nerve in Duane syndrome verified by magnetic resonance imaging<...
Ocular deficiencies in deaf children
Bilateral Abducens Nerve Palsy and Nystagmus Resolved Upon Intravenous Dextrose Administration in Hypoglycemic Young Female: A...
Transcranial magnetic stimulation of the oculomotor and abducens nerves: Determining the site of excitation in the cat<...
Isolated abducens nerve palsy associated with coronavirus disease: an 8-month follow-up. | Arq Bras Oftalmol;85(5): 517-519,...
Acute Disseminated Encephalomyelitis Differential Diagnoses
Primary CNS Lymphoma: Overview, Etiology, Epidemiology
外展神經 - 维基百科,自由的百科全书
The Neurologic Examination of Animals - Nervous System - Merck Veterinary Manual
Neuro-ophthalmologist - All About Vision
Dr. Enrique Serrano, MD, Clinical Neurophysiologist - Kissimmee, FL | Sharecare
Browse | jns Journals
Cranial mononeuropathy VI: MedlinePlus Medical Encyclopedia
Cranial Nerves Flashcards
Enterovirus 71 Outbreaks, Taiwan: Occurrence and Recognition - Volume 9, Number 3-March 2003 - Emerging Infectious Diseases...
Radioprotective effect of a pan-caspase inhibitor in a novel model of radiation injury to the nucleus of the abducens nerve
Bioline International Official Site (site up-dated regularly)
Ophthalmologic Manifestations of Myasthenia Gravis: Overview, Patient History, Physical Examination
Cranial nerve palsy8
- Sixth cranial nerve palsy affects the lateral rectus muscle, impairing eye abduction. (msdmanuals.com)
- However, the cause of an isolated 6th cranial nerve palsy is often not identified. (msdmanuals.com)
- Symptoms of 6th cranial nerve palsy include binocular horizontal diplopia when looking to the side of the paretic eye. (msdmanuals.com)
- Other tests may be done depending on the suspected cause of 6th cranial nerve palsy. (msdmanuals.com)
- The signs and symptoms of the cranial nerve palsy resolved within two weeks of initiating corticosteroid therapy. (elsevierpure.com)
- Ocular examination revealed a sixth cranial nerve palsy in the left eye . (bvsalud.org)
- The exact cause of vaccination-related cranial nerve palsy in children is not known. (medlineplus.gov)
- Childhood-onset of recurrent headaches with an oculomotor cranial nerve palsy. (nih.gov)
Diplopia8
- Damage to the peripheral part of the abducens nerve will cause double vision (diplopia), due to the unopposed muscle tone of the medial rectus muscle. (wikipedia.org)
- Complete interruption of the peripheral sixth nerve causes diplopia (double vision), due to the unopposed action of the medial rectus muscle. (wikipedia.org)
- The principal symptom of abducens nerve palsy is the presence of binocular horizontal diplopia , as the eye is not able to perform abduction, resulting in lateral displacement [4] [5]. (symptoma.com)
- Dysfunction of the nerve causes lateral rectus muscle weakness , resulting in horizontal diplopia that is maximal when the affected eye is abducted and esotropia. (symptoma.com)
- A 53-year-old male patient with diabetes presented 6 weeks after lumbar disc surgery with persistent headache, a fluctuant swelling at the operated site, and diplopia secondary to left abducens nerve palsy. (symptoma.com)
- McGee S. Nerves of the eye muscles (III, IV, and VI): approach to diplopia. (medlineplus.gov)
- Eye movement disorders: third, fourth, and sixth nerve palsies and other causes of diplopia and ocular misalignment. (medlineplus.gov)
- and TROCHLEAR NERVE are involved with DIPLOPIA and BLEPHAROPTOSIS . (nih.gov)
Left abducens nerve1
- Unilateral absence of the left abducens nerve was verified using magnetic resonance imaging. (nih.gov)
Nucleus12
- The abducens nucleus is located in the pons, on the floor of the fourth ventricle, at the level of the facial colliculus. (wikipedia.org)
- Axons from the facial nerve loop around the abducens nucleus, creating a slight bulge (the facial colliculus) that is visible on the dorsal surface of the floor of the fourth ventricle. (wikipedia.org)
- The abducens nucleus is close to the midline, like the other motor nuclei that control eye movements (the oculomotor and trochlear nuclei). (wikipedia.org)
- citation needed] Motor axons leaving the abducens nucleus run ventrally and caudally through the pons. (wikipedia.org)
- The central anatomy of the sixth nerve predicts (correctly) that infarcts affecting the dorsal pons at the level of the abducens nucleus can also affect the facial nerve, producing an ipsilateral facial palsy together with a lateral rectus palsy. (wikipedia.org)
- The sixth nerve nucleus is located in the pons, just ventral to the floor of the fourth ventricle and just lateral to the medial longitudinal fasciculus (MLF). (medscape.com)
- Damage to the sixth nerve nucleus results in an ipsilateral gaze palsy. (medscape.com)
- Healthy male Sprague‑Dawley rats were used in the present study to examine the radioprotective effect of a type of pan-caspase inhibitor, z-VAD-fmk, following radiation, to investigate the effects of caspase blockade in a model of the nucleus of the abducens nerve. (spandidos-publications.com)
- In the present study, a model of the nucleus of abducens nerve was established to examine this. (spandidos-publications.com)
- In most cases, the abducens nucleus and nerve are absent or hypoplastic, and the lateral rectus muscle is innervated by a branch of the oculomotor nerve. (bionity.com)
- In both cases the sixth cranial nerve nucleus was absent, as was the sixth nerve, and the lateral rectus muscle was innervated by the inferior division of the third or oculomotor cranial nerve. (bionity.com)
- A somatic motor nerve originating in the abducens nucleus in the pons. (unboundmedicine.com)
Trigeminal nerve1
- In 1904, Giuseppe Gradenigo (1859-1926), an Italian otolaryngologist, described a syndrome characterized by a triad of middle ear infection, ipsilateral abducent paralysis, and ipsilateral trigeminal neuropathic pain most commonly manifested as retroorbital pain due to irritation of the ophthalmic division of the trigeminal nerve. (medscape.com)
Paralysis5
- Palsy resulting from a cavernous sinus lesion can cause severe head pain, chemosis (conjunctival edema), anesthesia in the distribution of the 1st and 2nd division of the 5th cranial nerve, and paralysis of the 3rd, 4th, and 6th cranial nerves. (msdmanuals.com)
- Injury to this nerve results in lateral rectus muscle weakness or paralysis. (uchicago.edu)
- There is less chance of recovery in case of complete paralysis of the sixth nerve. (medlineplus.gov)
- However, for surgeries occurring distal to the elbow, a combination radial, ulnar, median, musculocutaneous block is chosen because this technique lacks many of the more serious complications such as pneumothorax, cervicothoracic ganglion block with Horner's syndrome and phrenic nerve paralysis. (asra.com)
- As the third cranial nerve controls many of the eye's muscles and functions, palsy of this nerve can result in complete or partial paralysis of the eye. (optometrists.org)
Abducent5
- The abducens nerve or abducent nerve, also known as the sixth cranial nerve, cranial nerve VI, or simply CN VI, is a cranial nerve in humans and various other animals that controls the movement of the lateral rectus muscle, one of the extraocular muscles responsible for outward gaze. (wikipedia.org)
- This brief article displays Pictures Of Abducent Nerve. (healthiack.com)
- This article is about Pictures Of Abducent Nerve. (healthiack.com)
- Interest in studying the anatomy of the abducent nerve arose from early clinical experience with abducent palsy seen in middle ear infection. (medscape.com)
- In 1905, an Italian anatomist, Primo Dorello (1872-1963), offered his own theory on the possible cause of abducent nerve palsy in Gradenigo syndrome based on anatomical dissections done to study the course of the abducent nerve. (medscape.com)
Inferior5
- It runs up and anterior to the pons and pierces the dura overlying the basilar part of the occipital bone and runs in Dorello's canal (piece of bone consisting of the inferior petrosal sinus and 6th nerve) prior to their entrance within the Cavernous Sinus. (myneurosurg.com)
- Inferior view of the human brain, with the cranial nerves labelled. (wikipedia.org)
- Arnold's nerve originates from the superior ganglion of the vagus nerve and also has a small contribution from the inferior ganglion of the glossopharyngeal nerve . (radiopaedia.org)
- the inferior alveolar nerves innervate the lower teeth and gingivae. (unboundmedicine.com)
- The inferior alveolar nerve (from CN V3) runs in the mandibular canal, giving off branches to the lower teeth and gingivae as it passes. (unboundmedicine.com)
Trochlear nerve1
- Fourth Nerve Palsy, also known as Superior Oblique Palsy or Trochlear Nerve Palsy, occurs when the fourth cranial nerve becomes diseased or damaged. (optometrists.org)
MeSH1
- Abducens Nerve Injury" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (uchicago.edu)
Palsy caused1
- This case suggests that isolated abducens nerve palsy caused by severe acute respiratory syndrome coronavirus 2 infection may improve with a conservative approach. (bvsalud.org)
Optic2
- Optic nerve swelling or jumpy eye movements (nystagmus) may occur at any age and warrants immediate work-up for a central nervous system tumor. (symptoma.com)
- Within the layers of the retina, photons trigger a series of electrical and chemical reactions, ultimately sending electrical signals by way of the optic nerve, along with visual pathway to the occipital cortex. (medscape.com)
Sixth nerve palsies3
- Sixth nerve palsies fall into the following categories: 3%-30% trauma, 0%-6% aneurysm, 0%-36% ischemic, 8%-30% idiopathic, and 10%-30% demyelination/miscellaneous. (medscape.com)
- Patients older than 55 years with isolated sixth nerve palsies may require a less aggressive initial workup if they have predisposing microvascular ischemic risk factors, but no history of cancer. (medscape.com)
- Abducens nerve palsies, or sixth nerve palsies, results in weakness of the ipsilateral lateral rectus muscle. (symptoma.com)
Lateral rectus9
- The abducens nerve supplies the lateral rectus muscle of the human eye. (wikipedia.org)
- The anatomy also predicts (correctly) that infarcts involving the ventral pons can affect the sixth nerve and the corticospinal tract simultaneously, producing a lateral rectus palsy associated with a contralateral hemiparesis. (wikipedia.org)
- Cranial nerve VI, also known as the abducens nerve, innervates the ipsilateral lateral rectus (LR), which functions to abduct the ipsilateral eye. (medscape.com)
- The abduces nerve then proceeds through the superior orbital fissure and innervates the lateral rectus muscle. (medscape.com)
- The abducens nerve (cranial nerve VI) is known for its very long travel from the brainstem to the ipsilateral lateral rectus muscle, where it provides an important function by stimulating abduction of the eye [1] [2]. (symptoma.com)
- The abducens nerve ( cranial nerve VI) is a motor nerve that supplies one of the extraocular muscles of the eye: the lateral rectus muscle. (neuroscientificallychallenged.com)
- The latencies of the motor responses of the superior rectus and lateral rectus were 1.08 ± 0.22 and 1.02 ± 0.21 msec, respectively, suggesting that magnetic stimulation excites both the oculomotor and the abducens nerve at the superior orbital fissure. (elsevierpure.com)
- The sixth cranial nerve is responsible for sending signals to the lateral rectus muscle. (optometrists.org)
- When the sixth cranial nerve becomes damaged, it prevents the lateral rectus muscle from operating and results in an inward eye turn (esotropia) and double vision. (optometrists.org)
Pons4
- citation needed] The abducens nerve emerges from the brainstem at the junction of the pons and the medulla, superior to the medullary pyramid, and medial to the facial nerve. (wikipedia.org)
- The human abducens nerve is derived from the basal plate of the embryonic pons. (wikipedia.org)
- Mass lesions that push the brainstem downward can damage the nerve by stretching it between the point where it emerges from the pons and the point where it hooks over the petrous temporal bone. (wikipedia.org)
- The abducens nerve emerges from the brainstem at the pontomedullary junction to enter the subarachnoid space, coursing upward between the pons and clivus to enter the Dorello canal. (medscape.com)
Nystagmus2
- MRI is indicated for any brainstem findings to exclude pontine glioma in children (most have papilledema and nystagmus without other cranial nerve involvement) and in adults who show no improvement. (medscape.com)
- clinical examination was within normal except for bilateral abducens palsy, horizontal nystagmus and photophobia. (e-jnic.org)
Subarachnoid space3
- The nerve enters the subarachnoid space (more precisely, the pontine cistern) when it emerges from the brainstem. (wikipedia.org)
- Certain authors have divided the pathologies that cause abducens nerve palsy according to their anatomical sites (the brain stem, subarachnoid space, the petroclival region, the cavernous sinus , and the orbit), and numerous conditions, both localized and systemic, may cause this condition [1] [2]. (symptoma.com)
- Then, papilledema , visual deficits, and symptoms suggestive of a central nervous system (CNS) infection of any etiology (bacterial, viral, fungal ) may be seen if the nerve is compromised in the subarachnoid space, as various tumors, sarcoidosis , pseudotumor cerebri and meningitis have been described as potential etiologies [1]. (symptoma.com)
VIth1
- A 45-year-old hemodialysis patient presenting with recurrence of SLE which manifested predominantly as a unilateral left abducens (VIth) nerve palsy is described. (elsevierpure.com)
Thoracic1
- Analgesia for thoracotomies may be provided via thoracic epidurals or paravertebral or intercostal nerve blocks (Figure 2). (asra.com)
VIII2
- Examination for a sixth nerve palsy involves documenting the presence or absence of papilledema, examining the ocular motility, evaluating the eyelids and pupils, and excluding involvement of other cranial nerves (eg, V, VII, VIII). (medscape.com)
- The components of the eighth cranial nerve (CN VIII) carrying axons that convey information regarding sound and balance between the spiral ganglion in the inner ear and the cochlear nuclei in the brainstem. (unboundmedicine.com)
Ocular3
- The sixth cranial nerve is the most commonly affected of the ocular motor nerves. (medscape.com)
- A 6th Nerve Palsy can be quite common in exams, as they can be caused via extra-ocular muscle pathology, rather than any intrinsic lesion in the brain, therefore it is still vitally important. (myneurosurg.com)
- Examples of these functions include vision (cranial nerve #2), pupil restriction and eyelid elevation (cranial nerve #3), and ocular mobility (cranial nerve #4). (allaboutvision.com)
Anatomy1
- In this video, I discuss the anatomy and function of the abducens nerve, as well as describe what can happen when the nerve is damaged. (neuroscientificallychallenged.com)
Diseases2
- Other processes that can damage the sixth nerve include strokes (infarctions), demyelination, infections (e.g. meningitis), cavernous sinus diseases and various neuropathies. (wikipedia.org)
- Abducens nerve palsy may occur due to a myriad of infectious, inflammatory, genetic, or malignant diseases. (symptoma.com)
Muscles3
- This misdirection of nerve fibres results in opposing muscles being innervated by the same nerve. (bionity.com)
- The posterior auricular nerve is a motor branch of the facial nerve (CN VII) that innervates the posterior and intrinsic auricular muscles. (unboundmedicine.com)
- The third cranial nerve controls the actions of four external eye muscles. (optometrists.org)
Injury9
- The long course of the abducens nerve between the brainstem and the eye makes it vulnerable to injury at many levels. (wikipedia.org)
- Iatrogenic injury is also known to occur, with the abducens nerve being the most commonly injured cranial nerve in halo orthosis placement. (wikipedia.org)
- Traumatic injury to the abducens, or sixth, cranial nerve. (uchicago.edu)
- This graph shows the total number of publications written about "Abducens Nerve Injury" by people in this website by year, and whether "Abducens Nerve Injury" was a major or minor topic of these publications. (uchicago.edu)
- Below are the most recent publications written about "Abducens Nerve Injury" by people in Profiles. (uchicago.edu)
- Nerve Root Injury and Plexus Disorders (incl. (sharecare.com)
- The chances of recovery are less in children than in adults in case of traumatic injury of the nerve. (medlineplus.gov)
- Symptoms of nerve injury include paresthesias, loss of sensation and position sense, impaired motor function, cranial nerve malfunction, changes in reflexes, and impairments in glandular secretion. (unboundmedicine.com)
- The assessment of nerve injury includes a careful neurological examination, sometimes accompanied by tests, e.g., electromyography or nerve conduction studies. (unboundmedicine.com)
Petrous temp2
- For example, fractures of the petrous temporal bone can selectively damage the nerve, as can aneurysms of the intracavernous carotid artery. (wikipedia.org)
- The 6th nerve has a significantly close relationship with the 7th nerve at the petrous temporal bone and greater superficial petrosal nerves. (myneurosurg.com)
Superior5
- The anterior superior alveolar nerves, branches of the infraorbital nerve (from CN V2), run in canals in the anterior wall of the maxillary sinus and innervate the upper incisors, canines, premolars, and often part of the first molar. (unboundmedicine.com)
- Sometimes there is a middle superior alveolar nerve that innervates the premolars and first molar. (unboundmedicine.com)
- The posterior superior alveolar nerves (also from CN V2) innervate the rest of the upper molars. (unboundmedicine.com)
- The auricular branch of the vagus nerve is a sensory nerve emerging from the superior ganglion of the vagus nerve, joined by branches from the glossopharyngeal (CN IX) and facial nerves, and innervating the lower part of the tympanic membrane and the floor of the external auditory canal. (unboundmedicine.com)
- The fourth cranial nerve controls the actions of the superior oblique eye muscle and is responsible for turning the eye inward and downward. (optometrists.org)
Lesion1
- Central nervous system lesions of the abducens nerve tract are localized easily secondary to the typical findings associated with each kind of lesion. (medscape.com)
Somatic2
- It is a somatic efferent nerve. (wikipedia.org)
- The abducens nerve carries axons of type GSE, general somatic efferent. (wikipedia.org)
Mandibular nerve1
- A sensory branch of the mandibular nerve (CN V3) It passes through the parotid gland en route to the ear, where it innervates skin of the pinna, external auditory canal, and tympanic membrane. (unboundmedicine.com)
Peripheral nerves1
- Multiple Mononeuropathy Multiple mononeuropathies are characterized by sensory disturbances and weakness in the distribution of ≥ 2 affected peripheral nerves. (msdmanuals.com)
Cavernous sinus1
- MRI provides greater resolution of the orbits, cavernous sinus, posterior fossa, and cranial nerves. (msdmanuals.com)
Potentials1
- The authors have attempted to stimulate the feline oculomotor and abducens nerves using a magnetic coil (MC) and to determine the optimal reliable MC position for eliciting motor evoked potentials. (elsevierpure.com)
Stimulation1
- Multiple approaches to femoral and sciatic nerve blockade have been described, including ultrasound guidance, electrolocation/ nerve stimulation, or both. (asra.com)
Clival1
- Abducens palsy can be a false localizing sign with lesions that cause increased intracranial pressure and stretching of the sixth nerve as it ascends the clival area. (medscape.com)
Sensory1
- Arnold's nerve , also known as the auricular branch or mastoid branch , of the vagus nerve (CN X) is a small sensory nerve supplying the skin of the external acoustic meatus. (radiopaedia.org)
Sympathetic1
- A sympathetic nerve to the heart that carries impulses that speed the heart rate. (unboundmedicine.com)
Disorder2
- Cranial mononeuropathy VI is a nerve disorder. (medlineplus.gov)
- Because there are common nerve pathways through the skull, the same disorder that damages the sixth cranial nerve may affect other cranial nerves (such as the third or fourth cranial nerve). (medlineplus.gov)
Axons2
- The neuronal cell bodies of a nerve's axons are in the brain, the spinal cord, or ganglia, but the nerves run only in the peripheral nervous system. (unboundmedicine.com)
- Nerves with axons that conduct electrochemical impulses toward the central nervous system (CNS) are afferent, nerves with axons that conduct impulses away from the CNS are efferent, and nerves with both afferent and efferent axons are mixed. (unboundmedicine.com)
Spinal1
- A nerve that conducts impulses toward the brain or spinal cord. (unboundmedicine.com)
Trauma1
- The nerve may be damaged by closed or penetrating CRANIOCEREBRAL TRAUMA or by facial trauma involving the orbit. (uchicago.edu)
Pathology1
- It is also responsible for the referred otalgia through the vagus nerve (CN X), in the case of laryngeal pathology. (radiopaedia.org)
Duane4
- Congenital sixth nerve palsy (Duane syndrome) is a well-recognized entity. (medscape.com)
- To demonstrate that currently available magnetic resonance imaging techniques may verify the absence of the abducens nerve in Duane syndrome. (nih.gov)
- We performed magnetic resonance imaging in a 36-year-old woman with left Duane syndrome, type 1, using spoiled gradient recalled acquisition in the steady state to obtain high-resolution T1-weighted images through the abducens nerve in its subarachnoid segment. (nih.gov)
- The absence of the abducens nerve in Duane syndrome can be verified by modern magnetic resonance imaging techniques. (nih.gov)
Magnetic1
- Neurological examinations including magnetic resonance imaging failed to identify the cause of abducens palsy. (elsevierpure.com)
Abduction1
- citation needed] Partial damage to the abducens nerve causes weak or incomplete abduction of the affected eye. (wikipedia.org)
Sciatic nerve2
- The pudendal nerve, derived from S2, S3 and S4, leaves the pelvis m edial to the sciatic nerve via the higher sciatic foram en. (dnahelix.com)
- Patients presenting for surgery of the pelvic limbs typically receive either an epidural or combination femoral and sciatic nerve blocks. (asra.com)
Fibers1
- Throughout the years, in the absence of ancillary or diagnostic tools, many descriptive phrases, clichés, or analogies have been used to describe the eye, such as "the eye is the window to the soul," the "eye works like a camera," and "the eye is the only structure that allows us to physically see blood vessels and nerve fibers. (medscape.com)