title: The anatomy of Meyer's loop revisited: changing the anatomical paradigm of the temporal loop based on evidence from fiber microdissection.
abstract: OBJECTIVE
  The goal in this study was to explore and further refine comprehension of the anatomical features of the temporal loop, known as Meyer's loop.
  
  
  METHODS
  The lateral and inferior aspects of 20 previously frozen, formalin-fixed human brains were dissected under the operating microscope by using fiber microdissection.
  
  
  RESULTS
  A loop of the fibers in the anterior temporal region was clearly demonstrated in all dissections. This temporal loop, or Meyer's loop, is commonly known as the anterior portion of the optic radiation. Fiber microdissection in this study, however, revealed that various projection fibers that emerge from the sublentiform portion of the internal capsule (IC-SL), which are the temporopontine fibers, occipitopontine fibers, and the posterior thalamic peduncle (which includes the optic radiation), participate in this temporal loop and become a part of the sagittal stratum. No individual optic radiation fibers could be differentiated in the temporal loop. The dissections also disclosed that the anterior extension and angulation of the temporal loop vary significantly.
  
  
  CONCLUSIONS
  The fiber microdissection technique provides clear evidence that a loop in the anterior temporal region exists, but that this temporal loop is not formed exclusively by the optic radiation. Various projection fibers of the IC-SL, of which the optic radiation is only one of the several components, display this common course. The inherent limitations of the fiber dissection technique preclude accurate differentiation among individual fibers of the temporal loop, such as the optic radiation fibers.
authors: 1Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey; and.|2Department of Anatomy, University of Medicine and Pharmacy Targu Mures, Romania.
authors: Cristina
authors: C
authors: Goga
authors: 1Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey; and.
authors: Uğur
authors: U
authors: Türe
mesh_terms: D006801:Humans; D009412:Nerve Fibers; D013702:Temporal Lobe / Q000033:anatomy & histology*; D014795:Visual Pathways / Q000033:anatomy & histology*
keywords: AC = anterior commissure; IC = internal capsule; IC-SL = sublentiform portion of the internal capsule; Meyer's loop; SS = sagittal stratum; fiber dissection technique; microsurgical anatomy; optic radiation; temporal loop; white matter anatomy