Artikel
The optic radiations: a microsurgical anatomic study
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
Using a fiber-dissection technique, our aim was to describe the myelined fiber bundles of the optic radiation. We focused on the course, the length and relations with neighbouring fasciculi and lateral ventricle.
Methods
We dissected ten previously frozen, formalin-fixed human brains under the operating microscope (with 6X to 40X magnification) using the fiber-dissection technique described by Klingler. The primary dissection tools were handmade, thin, wooden and curved metallic spatulas with tips of various sizes. Lateral and inferior approaches were made.
Results
The optic radiations called Gratiolet’s radiations extended from the lateral geniculate body to the occipital cortex. The average length of the optic radiation from the tip of Meyer’s loop to the calcarine fissure is 105 mm. The breadth of the optic radiation is 17 mm and became enlarged towards to occipital pole. This tract called geniculocalcarin is divided into 3 bundles: the ventral bundle forms the Meyer’s loop and is in relation to the tip of the temporal horn of the lateral ventricle. The central or middle bundle runs posteriorly along the lateral wall and roof of the atrium of the lateral ventricle. The dorsal bundle covers in a horseshoe the occipital diverticle of the lateral ventricle to reach the upper lip of the calcarine fissure. Adjacent anatomic structures are laterally the inferior longitudinal fasciculus, medially the tapetum of the corpus callosum and the ependyma of the lateral ventricle.
Conclusions
This study is beneficial to increasing our knowledge of brain anatomy, which is essential for neurosurgical approaches to avoid a damage of the optic radiations.