Ebook Human neuroanatomy (2/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Human neuroanatomy (2/E): Part 2
Ebook Human neuroanatomy (2/E): Part 2
CHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2ULAR MUSCLES13.5ANATOMICAL BASIS OF CONJUGATE OCULAR MOVEMENTS13.6MEDIAL LONGITUDINAL FASCICULUS13.7VESTIBULAR CONNECTIONS RELATED TO OCULAR MOVEMENTS13.8INJURY TO THE MEDIAL LONGITUDINAL FASCICULUS13.9VESTIBULAR NYSTAGMUS13.10THE RETICULAR FORMATION AND OCULAR MOVEMENTS13.11CONGENITAL NYSTAGMUS13.1 Ebook Human neuroanatomy (2/E): Part 22OCULAR BOBBING13.13EXAMINATION OF THE VESTIBULAR SYSTEM13.14VISUAL REFLEXESFURTHER READING13.1OCULAR MOVEMENTS13.1.1Primary position of the eyesNormaEbook Human neuroanatomy (2/E): Part 2
lly our eyes look straight ahead and steadily fixate on objects in the visual field. This is the primary position (Figs 12.3 and 13.1) of the eyes, inCHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2ry position is also termed the position of fixation or ocular fixation. The position of rest for the eyes exists in sleep when the eyelids are closed. In the newborn, the eyesoften mow separately. Ocular fixation and coordinalion of ocular movements lake place by about 3 months of ago.13.2CONJUGATE Ebook Human neuroanatomy (2/E): Part 2OCULAR MOVEMENTSMoving our eyes, head, and body increases our range of vision. Under normal circumstances, both eyes move in unison (yoked together orEbook Human neuroanatomy (2/E): Part 2
conjoined) and in the same direction. Them are several types of such movements, termed conjugate ocular movements: (1) miniature ocular movements, (2CHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2. James R Augustine.& 2017 John Wiley & Sons, Inc. Published 2017 by John Wiley & Sons, Inc.Companion website: www.wiley.com/go/Augustine/HumanNeuroanatomy2e208 ••• CHAPTER 13each other but with equal magnitude, when both eyes turn medially to a common point such as during convergence of the eyes. S Ebook Human neuroanatomy (2/E): Part 2uch nonconjugate ocular movements an* termed vergence movements.13.2.1Miniature ocular movementsBecause of a continuous stream of impulses to the extrEbook Human neuroanatomy (2/E): Part 2
aocular muscles from many sources, the eyes are constantly in motion, making as many as 33 back and forth miniature ocular movements per second. TheseCHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2ovements in that they are smaller than voluntary ocular movements and occur during efforts Io stabilize the eyes and maintain them in the primary position. These miniature ocular movements enhance the clarity of our vision. The an.' minute is a unit of angular measurement lhal corresponds to one-six Ebook Human neuroanatomy (2/E): Part 2tieth of a degree. Each arc minute is divisible into 60 arc seconds. During these miniature ocular movements, the eyes never travel far from their priEbook Human neuroanatomy (2/E): Part 2
mary position only about 2 5 minutes of arc cm the horizontal or vertical meridian, lhe retinal image of the target remains centered on a few receptorCHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2cks (small, rapid changes in eye position, 1-3 per second, and about 6minutes of arc), drifts (occurring over an arc of about 5 minutes), and physiological nystagmus (consisting of high-frequency tremors of the order of 50-100 Hz with an average amplitude of less than 1 minute of arc - 5-30 arc seco Ebook Human neuroanatomy (2/E): Part 2nds is normal).1.3.2.2 SaccadesIn addition to miniature ocular movements, two other types of voluntary ocular movements are recognized. Saccades (scanEbook Human neuroanatomy (2/E): Part 2
ning or rapid ocular movements) are high-velocity movements (angular velocity of 40Ư 6UUự S'1) that direct die fovea from object to object in the shorCHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2yes move from word to word between periods of fixation. These periods of fixation may last 200-300 ms. The largo saccade that changes fixation from the end of one lino to the beginning of the next is termed the return sweep. Humans make thousands of saccades daily that are seldom larger titan 5“ and Ebook Human neuroanatomy (2/E): Part 2 take about 40 50 ms. In normal reading, such movements are probably 2” or less and take about 30 ms. 1 fence saccades are fast, brief, and accurate mEbook Human neuroanatomy (2/E): Part 2
ov entente brought about by a large burst of activity in the agonistic muscle (Literal rectus), with simultaneous and complete inhibition or silencingCHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCU Ebook Human neuroanatomy (2/E): Part 2 al the endInferior obĩque: elevates adducted eyeballSuperior rectus: elevates abducted eyeballSuperior oblique:.. 7depresses abducted-------CHAPTER 13Ocular Movements and Visual Reflexes13.1OCULAR MOVEMENTS13.2CONJUGATE OCULAR MOVEMENTS13.3EXTRAOCULAR MUSCLES13.4INNERVATION OF THE EXTRAOCUGọi ngay
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