Frank Mihlon Last partial edit 9/16/12 Brain Anatomy Outlines Note: Please email errors to [email protected] so I can update the outlines. Gyri (sources: Duvernoy. The Human Brain. 1999 and Stippich. Clinical functional MRI. 2007) • Frontal Lobe gyri o Precentral Gyrus o Superior frontal gyrus (F1) o Middle frontal gyrus (F2) o Inferior frontal gyrus (F3) ! Pars orbitalis (rostrally) ! Pars triangularis (mid) • (PO + PT = frontal operculum) ! Pars opercularis (caudally) o Frontal pole (rostral merging of the three major gyri) ! Superior frontopolar gyrus ! Inferior frontopolar gyrus ! Variable: middle frontopolar gyrus ! Variable: frontomarginal gyrus • Orbital lobe (inferior surface of frontal lobe) o Gyrus rectus (part of F1) o Medial orbital gyrus (part of F1) o Anterior orbital gyrus (part of F2) o Lateral orbital gyrus (part of F2 rostrally and F3 caudally) o Posterior orbital gyrus (part of F3) • Insula (Island of Reil) o 3 Short insular gyri (rostrally) o 2 Long insular gyri (caudally) o Limen insulae ! small gyrus that connects the frontal lobe (posterior orbital gyrus) and insula ! lateral to the anterior perforated substance ! floor (note: I think the roof) of the basal part of the lateral fissure • Temporal lobe gyri o Superior temporal gyrus (T1) (3 parts) ! Planum polare (rostrally) ! Anterior and Posterior Transverse temporal gyri (of Heschl) ! Planum temporale (caudally) o Middle temporal gyrus (T2) o Inferior temporal gyrus (T3) o Temporal pole (rostral merging of the three major gyri) o Fusiform gyrus (T4) (aka lateral occipitotemporal gyrus) • Limbic gyrus (4 parts) o Subcallosal gyrus o Cingulate gyrus o Isthmus (aka Retrosplenial gyrus)(joins parahippocampal gyrus to cingulate gyrus under splenium) o Parahippocampal gyrus (T5) ! Subiculum • narrow posterior segment • connects hippocamus to parahippocampal gyrus ! Piriform lobe (bulbous anterior segment) • Uncus, anterior part o Semilunar gyrus o Gyrus ambiens • Entorhinal area o Intralimbic gyrus (3 parts: anterior, superior, inferior) ! Prehippocampal rudiment (tiny anterior part; vestigial remnant) ! Indusium griseum (superior part betWeen cingulate and callosum; vestigial remnant) ! Hippocampus (bilaminar inferior part; consists of head, body, and tail) • Cornu ammonis (CA1, CA2, CA3, CA4) • Dentate gyrus (rolled inside cornu ammonis) o (medial occipito-temporal gyrus = T5 parahippocampal gyrus + O5 lingual gyrus) • Parietal lobe gyri o Postcentral gyrus ! Two connections to precentral gyrus (forms a donut) • Subcentral gyrus (ventrally) • Paracentral lobule (dorsally) o Superior parietal lobule (P1) ! Precuneus (medial aspect betWeen pars marginalis and parieto-occipital fissure) ! (first parieto-occipital arcus [“pli de passage” of Gratiolet] merges superior parietal lobule with superior occipital gyrus) o Inferior parietal lobule (P2) ! Supramarginal gyrus (rostrally) ! Angular gyrus (caudally) ! (second parieto-occipital arcus [“pli de passage” of Gratiolet] merges angular gyrus with the middle occipital gyrus) ! (Temporo-occipital arcus merges angular gyrus With superior temporal gyrus) • Occipital lobe (O1-O6 + gyrus descendens of Ecker) o Superior occipital gyrus (O1) (merges With cuneus O6 medially) o Middle occipital gyrus (O2) (laterally) ! Superior part ! Inferior part o Inferior occipital gyrus (O3) o Occipital pole (caudal merging of the three major gyri) o Fusiform gyrus (O4) (T4 fusiform + O4 fusiform = Lateral occipito-temporal gyrus) o Lingual gyrus (O5) (O5 lingual + T5 parahippocampal = Medial occipito-temporal Gyrus) o Cuneus (O6) (well defined betWeen parieto-occipital fissure and calcarine sulcus) o Gyrus descendens (of Ecker) (small superficial vertical gyrus at occipital pole) • Opercula (4) (covering of the insula; latin “little lid”) o Frontal (posterior part of inferior frontal gyrus) ! Pars triangularis ! Pars opercularis o Central (subcentral gyrus) o Parietal (supramarginal gyrus) o Temporal (superior aspect of superior temporal gyrus) Sulci (sources: Duvernoy. The Human Brain. 1999 and Stippich. Clinical functional MRI. 2007) • Lateral fissure (Sylvian fissure) (tWo parts: basal and lateral) o Lateral part (3 segments and 5 major rami) ! Anterior segment (two rami that divide the inferior frontal gyrus) • Anterior horizontal ramus • Anterior ascending ramus ! Middle segment • Posterior horizontal ramus • Minor arms o Anterior subcentral sulcus o Posterior subcentral sulcus o Transverse temporal sulci (outline gyri of Heschle) ! Posterior segment • Posterior ascending ramus ! Posterior descending ramus o Basal part (aka Sylvian cistern) ! Falciform fold marks boundary betWeen lateral and basal part ! Limen insula forms floor of basal part (note: I think it forms the roof) • Frontal lobe o Superior frontal sulcus => superior precentral sulcus o Inferior frontal sulcus => inferior precentral sulcus o *variant: single precentral sulcus o *variant: longitudinal sulcus: extra, sometimes discontinuous, sulcus dividing superior frontal gyrus o *variant: middle frontal sulcus dividing middle frontal gyrus into into a superior and an inferior part and continuing anteriorly as the frontomarginal sulcus. The frontomarginal sulcus creates the frontomarginal gyrus inferiorly by dividing the inferior transverse frontopolar gyrus. o *variant: lateral orbital sulcus betWeen the frontal and orbital lobes, ie, betWeen the inferior frontal gyrus and lateral orbital gyrus o *variant: sulcus triangularis: groove from inferior frontal sulcus that cuts the pars triangularis o *variant: sulcus diagonalis: groove from anterior ascending ramus that cuts the pars opercularis • Orbital lobe o Medial orbital sulcus ! aka Olfactory sulcus ! betWeen gyrus rectus and medial orbital gyrus o H-shaped orbital sulcus (beWeen the four orbital gyri) o Arcuate orbital sulcus ! divergent ramus of the posterior lateral part of the H-shaped orbital sulcus ! betWeen lateral/medial orbital gyri and posterior orbital gyrus • Central sulcus (of Rolando) o *variant: gyrus bridging precentral and postcentral gyrus that divides the central sulcus into a superior segment and inferior segment • Insular sulci o Circular sulcus (separates insular cortex from lateral opercular cortex) o Central insular sulcus (divides anterior from posterior parts) o Falciform fold ! notch at the apex of the inverted triangle that is the insula ! boundary betWeen lateral and basal parts of the lateral fissure • Temporo-occipital incisure • Temporal lobe o Superior temporal sulcus (2 segments) (aka parallel sulcus) ! Anterior segment, reaches temporal pole ! Posterior segment (branches posteriorly into 2 segments that create the “M” shape of the angular gyrus) • Ascending posterior segment (aka Sulcus Angularis) • Horizontal posterior segment o Inferior temporal sulcus ! Usually not continuous and difficult to identify ! Posterior end may slope upWard and be called anterior occipital sulcus o Collateral sulcus ! (aka Medial occipitotemporal sulcus) ! Separates parahippocampal gyrus from inferior temporal gyrus anteriorly and fusiform gyrus (lateral occipitotemporal gyrus) posteriorly ! 2 rami that project inferolaterally • Anterior transverse collateral sulcus • Posterior transvers collateral sulcus o Lateral occipitotemporal sulcus (betWeen T4 fusiform/lateral occipitotemporal gyrus and T3 inferior temporal gyrus) • Intraparietal sulcus (3 segments) o Ascending segment ! aka inferior postcentral sulcus ! parallel to central sulcus o Horizontal segment (separates superior from inferior parietal lobule) ! Primary intermediate sulcus (of Jensen) • Descending ramus off the horizontal segment • separates marginal from angular gyrus ! Transverse parietal sulcus arises superiorly from the horizontal segment as a medial continuation of the intraparietal sulcus that splits the precuneus (medial surface of superior parietal lobule) and continues inferocaudally as the subparietal sulcus (part of the limbic fissure) o Descending segment (crosses theoretical lobar border to continue as the intraoccipital sulcus aka superior occipital sulcus) • Superior postcentral sulcus (isolated sulcus that splits the postcentral gyrus) • Occipital lobe o Lateral surface ! Superior occipital sulcus • aka intraoccipital sulcus • continuation of the intraparietal sulcus • terminates in the Transverse Occipital Sulcus ! Middle occipital sulcus (variable) • Splits middle occipital gyrus • Sulcus semilunatus (variable) posterior ramus of the middle occipital sulcus ! Inferior occipital sulcus (variable) o Medial and inferior surface ! Parietooccipital sulcus ! Calcarine sulcus • separates O6 cuneus from O5 lingual gyrus • 3 segments o middle: calcarine sulcus proper o anterior: anterior calcarine sulcus ! continuation of the junction of calcarine and occipito- parietal sulci ! part of limbic fissure o posterior: retrocalcarine sulcus ! Collateral sulcus, occipital part (aka medial occipitotemporal sulcus) • Limbic fissure (succession of 6 different and discontinuous sulci) o Anterior para-olfactory sulcus (aka subcallosal sulcus) ! Posterior branch of susorbital sulcus ! Divides subcallosal gyrus (beneath CC genu) from orbital lobe anteriorly o Cingulate sulcus ! aka Callosomarginal sulcus ! marginal segment aka pars marginalis o Subparietal sulcus (between precuneus and cingulate gyrus) o Anterior calcarine sulcus (betWeen isthmus and O5 lingual gyrus) o Collateral sulcus ! (aka Medial occipitotemporal sulcus) ! Separates parahippocampal gyrus from inferior temporal gyrus anteriorly and fusiform gyrus (lateral occipitotemporal