[Insular-opercular associative tracts: Review of their anatomy and relevance for the trans-opercular approach to the insula].

Introduction: The insula is a highly connected area, as an intricate network of afferent and efferent projections connect it with adjacent and distant cortical regions.

Objective: To perform an extensive review of recent literature to analyse the anatomy of the associative tracts related to the insula.

Results: The frontal aslant tract, arcuate fasciculus, horizontal portion of the superior longitudinal fasciculus and the middle longitudinal fasciculus are associative tracts connected to the opercula. The inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus run under the anterior and inferior portion of the insula.

Conclusions: the pars triangularis and orbicularis of the inferior frontal gyrus, as well as the middle and anterior part of the superior temporal gyrus, have few connections with the perisylvian associative network. Consequently, in the trans-opercular approach to the insula, these 2 regions represent anatomical corridors that give access to the insula. The IFOF and the uncinate fasciculus represent the deep functional margin of resection.