title: Microsurgical anatomy of the optic radiation and related fibers in 3-dimensional images.
abstract: BACKGROUND
  The fiber dissection technique provides unique 3-dimensional anatomic knowledge of the white matter.
  
  
  OBJECTIVE
  To examine the optic radiation anatomy and its important relationship with the temporal stem and to discuss its findings in relation to the approaches to temporal lobe lesions.
  
  
  METHODS
  We studied 40 cerebral hemispheres of 20 brains that had been fixed in formalin solution for 40 days. After removal of the arachnoid membrane, the hemispheres were frozen, and the Klingler technique was used for dissection under magnification. Stereoscopic 3-dimensional images of the dissection were obtained for illustration.
  
  
  RESULTS
  The optic radiations are located deep within the superior and middle temporal gyri, always above the inferior temporal sulcus. The mean distance between the cortical surface and the lateral edge of the optic radiation was 21 mm. Its fibers are divided into 3 bundles after their origin. The mean distance between the anterior tip of the temporal horn and the Meyer loop was 4.5 mm, between the temporal pole and the anterior border of the Meyer loop was 28.4 mm, and between the limen insulae and the Meyer loop was 10.7 mm. The mean distance between the lateral geniculate body and the lateral margin of the central bundle of the optic radiation was 17.4 mm.
  
  
  CONCLUSIONS
  The white matter fiber dissection reveals the tridimensional intrinsic architecture of the brain, and its knowledge regarding the temporal lobe is particularly important for the neurosurgeon, mostly because of the complexity of the optic radiation and related fibers.
authors.affiliation: Institute of Neurological Sciences, Microneurosurgery Laboratory, Beneficência Portuguesa Hospital, São Paulo, SP, Brazil.
authors.forename: Richard Gonzalo
authors.initials: RG
authors.lastname: Párraga
authors.forename: Guilherme Carvalhal
authors.initials: GC
authors.lastname: Ribas
authors.forename: Leonardo Christiaan
authors.initials: LC
authors.lastname: Welling
authors.forename: Raphael Vicente
authors.initials: RV
authors.lastname: Alves
authors.forename: Evandro
authors.initials: E
authors.lastname: de Oliveira
mesh_terms: D002102:Cadaver; D006801:Humans; D021621:Imaging, Three-Dimensional; D013702:Temporal Lobe / Q000033:anatomy & histology*; D014795:Visual Pathways / Q000033:anatomy & histology*