…By the Way, Where Is the Fornix???

…By the Way, Where Is the Fornix???

Resources …By the way, – H. Blumenfeld. Neuroanatomy through clinical cases where is the fornix??? (Sinauer 2002). – Digital anatomist: • http://www9.biostr.washington.edu/da.html An introduction to gross neuroanatomy –Sylvius: • http://www.sylvius.com/ Marco L. Loggia, PhD [email protected] Some slides kindly provided by E. Duerden, UMontreal. Brigham and Women’s Hospital (Anesthesiology) Mass General Hospital (Psychiatry) All images and animations included in this presentation are from the Digital Harvard Medical School Anatomist website, unless otherwise specified. Orientation Orientation Humans, however, have an upright posture… VENTRAL = towards the belly (=‘ventrum’ in latin) DORSAL = towards the back (=‘dorsum’in latin) ROSTRAL = towards the snout (‘rostrum’=beak in latin) ABOVE CAUDAL = towards the tail (=‘cauda’ in latin) M-D junction BELOW M-D junction In animals with a linear organization of the CNS, terminology is straightforward: = Watch out! ‘Superior’=‘Dorsal’ above the midbrain; =‘Rostral’ in the midbrain or below Blumenfeld, 2002. © Sinauer (2002) Sylvius.com Blumenfeld (adapted). © Sinauer (2002) 1 Orientation Orientation MEDIAL = close to the midline LATERAL = close to the sides Horizontal (axial/transverse) Coronal Sagittal LATERALMEDIAL LATERAL Horizontal Sagittal Coronal Think about the horizon! Imagine a tiara-like crown! Think about the bow of an archer! VENTRAL Blumenfeld. © Sinauer (2002) Major subdivisions Orientation of the encephalon Telencephalon Horizontal (axial/transverse) Coronal Sagittal -Cereb. Hemispheres (including cortex and subcortical structures) Diencephalon -thalamus -hypothalamus -other associated structures Horizontal Sagittal Coronal Brainstem -Midbrain (mesencephalon) -Pons* Think about the horizon! Imagine a tiara-like crown! Think about the bow of an archer! -Medulla oblongata (myelencephalon) Cerebellum* Sylvius.com * Pons+cerebellum = metencephalon 2 The brainstem The brainstem Cerebral peduncles Midbrain Midbrain Pons Pons Medulla Oblongata Medulla Oblongata Cranial nerves Inferior Olives Pyramids Cerebellum The brainstem The brainstem Sup. colliculus Midbrain Inf. colliculus Pons Cerebellar Medulla Peduncles Oblongata 3 The brainstem The brainstem Tips to find the medulla on axial slices: I can see two ventral ‘bumps’ (PYRAMIDS) Midbrain Pons Lateral to these, two more subtle ‘bumps’ Medulla Oblongata (INF. OLIVES) I am the level of the MEDULLA! Cerebellum The brainstem The brainstem Tips to find the pons on axial slices: Tips to find the midbrain on axial slices: I can see the large ‘belly’ I see MICKEY! (the ears=cerebral peduncles) I am the level of the PONS! I am the level of the MIDBRAIN! 4 The diencephalon The diencephalon The ICECREAM tip: Thalamus is the SCOOP, the hypothalamus the CONE! Hypothalamic sulcus Thalamus Hypothalamus The diencephalon The diencephalon Optic Optic chiasm chiasm Infundibulum of the pituitary gland Infundibulum Hypothalamus lies of the Pituitary dorsal to these structures gland Mammillary bodies Mammillary bodies 5 The diencephalon The diencephalon Thalami The ventricular system The ventricular system Lateral v. Lateral ventricles (inside the hemispheres) Third v. Cerebral aqueduct (tiny canal inside the midbrain) Cerebral aqueduct Third ventricle (between the 2 thalami; Fourth Fourth v. & at the center of the hypothalamus) ventricle (between pons/upper medulla and cerebellum) 6 The ventricular system Cerebral Hemispheres Foramen of Monro Third ventricle • 2 hemispheres, interconnected by: corpus callosum, anterior commissure, posterior commissure and (in some individuals) interthalamic adhesion (aka massa intermedia). Cerebral aqueduct Fourth ventricle Corpus callosum Thalamus Anterior Hypothalamus Commissure (tip: rostral to the fornix!) Midbrain Pons Posterior commissure (tip: dorsal to the top of the aqueduct!) Medulla Oblongata Cerebellum Cerebral Hemispheres Cortex • 2 hemispheres, interconnected by: corpus callosum, anterior commissure, posterior commissure and (in some individuals) interthalamic adhesion. • Composed of GYRI (the ‘HILLS’) and SULCI (the ‘VALLEYS’) • In each hemisphere: cortex (gyri, sulci), white matter and subcortical structures • If a sulcus is very deep Î FISSURE (E.g. Lateral fissure) (including hippocampus, amygdala and basal ganglia). • Some sulci run LONGITUDINALLY, others in a MEDIAL-LATERAL direction • 4 ‘undisputed’ lobes (frontal, parietal, temporal and occipital) + insula (sometimes referred to as ‘the fifth lobe’). 7 Cortex Cortex Central (Rolandic) fissure Parieto-occipital fissure PARIETAL LOBE FRONTAL LOBE OCCIPITAL LOBE TEMPORAL LOBE Lateral (Sylvian) fissure Preoccipital notch © Beal, LSU (2005). Modified Cortex Cortex Post central gyrus Central sulcus Tips to find the central sulcus: superior parietal lobule precentral gyrus 1) SFS stops at the precentral gyrus; 2) Look for the ‘Omega shape’ (motor hand area) Superior frontal Intraparietal fissure gyrus middle frontal gyrus Inferior parietal lobule inferior frontal gyrus superior temporal gyrus Lateral sulcus middle temporal gyrus From Emma Duerden, Inferior temporal gyrus with permission (modified) Courtesy of Digital Anatomist Project at Univ of Washington 8 Cortex Cortex Tip to find the intraparietal sulcus: The lateral fissure and superior temporal sulcus stop at the Inf par lobule © Cortex Cortex Parieto-occipital Cingulate gyrus fissure cuneus Calcarine fissure uncus Lingual gyrus Parahippocampal From Emma Duerden, Blumenfeld, 2002. © Sinauer (2002) gyrus Courtesy of Digital Anatomist Projectwith at Univ. permission of Washington 9 Cortex Cortex Insula Heschl’s (transverse) gyri From Emma Duerden, From Emma Duerden, Digital Anatomist Project at Univ. of Washington modified, with permission Digital Anatomist Project at Univ. of Washington with permission (modified) Hippocampus Hippocampus Tip to find the hippocampus: Look below the inferior horn of the lateral ventricle! Hippocampus The fornix connects the hippocampus to the mammillary bodies Lateral ventricle Inferior horn of the lateral ventricle Hippocampus Fornix (the axons of the hippocampal neurons) Blumenfeld, 2002. © Sinauer (2002) 10 Hippocampus and Amygdala The basal ganglia Tip to find the amygdala: Look rostral to the hippocampus! Amygdala Caudate nucleus Lentiform nucleus (=putamen+ globus pallidus) Hippocampus Blumenfeld, 2002. © Sinauer (2002) The basal ganglia The basal ganglia Tips to find the basal ganglia: 1) The nucleus bulging into the lateral ventricle is the head of the caudate 2) look for the L shaped white matter (internal capsule)! 3) ‘Pallidus’ means ‘pale’…. Anterior limb of the Internal capsule: separates caudate from lentiform Caudate n. (head) nucleus Lentiform nucleus Posterior limb of the (putamen) Internal capsule: separates thalamus Lentiform nucleus from lentiform (globus pallidus) nucleus Thalamus 11 The basal ganglia Tips to find the basal ganglia: 1) The nucleus bulging into the lateral ventricle is the head of the caudate 2) look for the L shaped white matter (internal capsule)! 3) ‘Pallidus’ means ‘pale’…. Anterior limb of the Internal capsule: separates caudate from lentiform Caudate n. (head) Thanks! nucleus Lentiform nucleus Posterior limb of the (putamen) Internal capsule: separates thalamus Lentiform nucleus from lentiform (globus pallidus) nucleus Thalamus 12.

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