الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The vestibular, visual, and somatosensory systems work together to maintain postural equilibrium and motion perception. The vestibular system has 3 important actions: control eye movement (maintaining binocular foveal fixation during head or body movement), acts as motion sensor and controls posture and equilibrium. The peripheral vestibular system consists of 3 semicircular canals (SCC) that are sensitive to angular accelerations, 2 otoliths (utricle and saccule) that are sensitive to linear accelerations and gravity, the hair cells and the vestibular nerve up to the root entry zone in the brain stem. The most important anatomical structure of the vestibular system is the VOR, which acts as gaze stabilizing system that produce an eye movement equal in magnitude but opposite in direction to head movement. VOR has three major planes of action which represent the three-dimensional (3-D) space. It connects a set of extraocular eye muscles that are aligned by their primary direction of pull with the same particular spatial plane of the three SCC. The canals of both labyrinths form functional pairs in the horizontal and vertical working planes. So nystagmus is used in defining and localizing vestibular pathology. from the history the physician should have general idea of whether the symptoms are attributable to a vestibular disorder and if so, whether this disorder is central or peripheral. Bedside examination, ear examination, general examination with an emphasis on vital signs, complete cardiovascular and neurologic examinations. Electronystagmography/ or Videonystagmography (VNG) with caloric testing is often the most sensitive determinant of vestibular dysfunction. Acute dizziness and vertigo is usually managed by medical treatment which should be used for few days at most. vestibular rehabilitation exercises is indicated in selected cases, while the surgical treatment of vertigo is indicated in selected cases or if failed medical treatment with severely intractable symptoms.