Anatomic relationships along the low-middle convexity: Part II: Lesion Localization

Author(s): Naidich TP,Valavanis AG,Kubik S, Taber Kh,Yasargil MG, et al.


Sagittal sections of anatomic specimens and magnetic resonance images well display the individual gyri and sulci along the low-middle convexity. Those familiar with the typical pattern and with the common normal variations will be able to use sagittal magnetic resonance imaging to correctly localize lesions by identifying: (a) the five major rami of the sylvian fissure; (b) the subdivision of the triangular inferior frontal gyrus into the M-shaped partes orbitalis, triangularis, and opercularis by the anterior horizontal and anterior ascending rami of the sylvian fissure; (c) the zig-zag shape of the middle frontal gyrus, which characteristically angles sharply and inferiorly to fuse with the anterior surface of the precentral gyrus; (d) T-shaped bifurcation of the posterior end of the inferior frontal sulcus to form the inferior precentral sulcus; (e) separation of the central sulcus from the sylvian fissure by union of the opercular ends of the precentral and postcentral gyri to form the subcentral gyrus inferior to the central sulcus; (f) narrower sagittal dimension of the postcentral gyrus than the precentral gyrus; (g) horseshoe shape of the supramarginal gyrus perched atop the posterior ascending ramus of the sylvian fissure; (h) similar horseshoe shape of the angular gyrus perched atop the posterior end of the superior temporal sulcus; (i) commonly intercalated accessory presupramarginal and preangular gyri; and (j) the arcuate course of the intraparietal sulcus, which separates the superior from the inferior parietal lobules. The anatomic relationships described are more nearly constant anteriorly than posteriorly. When used as described, they prove helpful in correctly localizing pathology and in planning a surgical approach to lesions that may be difficult to localize on the basis of axial or coronal plane magnetic resonance images.

Similar Articles

Consensus recommendations for MS cortical lesion scoring using double inversion recovery

Author(s): Geurts J, Roosendaal S, Calabrese M,Ciccarelli O,Agosta F,et al.

Location of the central sulcus via cortical thickness of the precentral and postcentralgyri on MR

Author(s): Meyer JR,Roychowdhury S, Russell EJ, Callahan C,Gitelman D,et al.

An MR protocol for presurgical evaluation of patients with complex partial seizures of temporal lobe origin

Author(s): Achten E, Boon P, De Poorter J,Calliauw L, Van De Kerckhove, et al.

Bias prevalence and kappa

Author(s): Byrt T, Bishop J, Carlin JB

Topography and identification of the inferior precentral sulcus in MR imaging

Author(s): Ebeling U, Steinmetz H, Huang Y, Kahn T