Description of sulcal organization of the insular cortex.

Purpose: To study the morphology of the gyri and sulci of the insular region.

Materials And Methods: This study examined 20 formalin-fixed cerebral hemispheres (10 right and 10 left). Observations described: the peri-insular sulci, anatomical variations in the insular sulci and gyri, and the relationships between the central insular sulcus and the central cerebral sulcus and the anatomy of the insular arteries.

Results: Each insula had a trapezoid shape, surrounded by four peri-insular sulci (anterior, superior, posterior, and inferior). We differentiated the posterior peri-insular sulcus from the inferior peri-insular sulcus. These two sulci have two different axes separated by a clear angle. The central insular sulcus divides the insula into two parts. The anterior insula includes three short gyri and the anterior insular pole. The posterior insula includes two long gyri and the posterior insular pole. This structure defines two intra-insular opercula. In 60% of cases, the superior extremity of the central insular sulcus is in direct continuity with the inferior extremity of the cerebral central sulcus. The superior branch of the middle cerebral artery supplies the majority of the anterior insular gyri, and the inferior branch supplies the majority of the posterior insular gyri.

Conclusions: This study details the morphology of each insular structure (gyri, sulci and poles), data which could facilitate surgical access to this deep cortical area and assist in future work correlating anatomy with function.