title: Microsurgical anatomy of the temporal stem: clinical relevance and correlations with diffusion tensor imaging fiber tracking.
abstract: OBJECTIVE
  The authors used a fiber dissection technique to describe the temporal stem and explain the tendency of malignant tumors to spread within both the frontal and temporal lobes. The authors focused on the morphological characteristics and course of various fasciculi of the temporal stem, including the uncinate fascicle, occipitofrontal fascicle, anterior commissure, loop of the optic radiations (Meyer loop), and the ansa peduncularis.
  
  
  METHODS
  Eight previously frozen, formalin-fixed human brains were dissected under an operating microscope using the fiber dissection technique described by Klingler. Lateral, inferior, and medial approaches were made. Cross-sectional 3D MR images obtained in 10 patients without brain lesions demonstrated that fibers of the temporal stem, which were intermingled together in various ways, curved laterally within the basal forebrain. Various pathological entities affecting the temporal stem are described and discussed.
  
  
  RESULTS
  The uncinate fascicle has 3 portions: a ventral extension, an intermediary segment called the isthmus, and a dorsal segment. The inferior occipitofrontal fasciculus is a layer of more superficial white matter that appeared to be superior to the uncinate fasciculus. A short ventral portion of the radiations of the corpus callosum was sometimes noted to run ventrally to enter the temporal stem and to reach both temporal lobes.
  
  
  CONCLUSIONS
  To the authors' knowledge, a detailed anatomy of the temporal stem has not been previously described in the literature. The unique anatomy of the temporal stem provides a route for tumor spread between the frontal and temporal lobes.
authors.affiliation: Laboratoire d'Anatomie et d'Organogenèse, Université de Picardie Jules Verne, Amiens, France. peltier.johann@chu-amiens.fr
authors.forename: Johann
authors.initials: J
authors.lastname: Peltier
authors.forename: Sébastien
authors.initials: S
authors.lastname: Verclytte
authors.forename: Christine
authors.initials: C
authors.lastname: Delmaire
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Pruvo
authors.forename: Olivier
authors.initials: O
authors.lastname: Godefroy
authors.forename: Daniel
authors.initials: D
authors.lastname: Le Gars
mesh_terms: D003337:Corpus Callosum / Q000473:pathology / Q000601:surgery; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008866:Microsurgery / Q000295:instrumentation*; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D013702:Temporal Lobe / Q000473:pathology* / Q000601:surgery*