DOCSLIB.ORG

A Pictorial Essay on Anatomy and Pathology of the Hippocampus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Pictorial Essay on Anatomy and Pathology of the Hippocampus Insights Imaging DOI 10.1007/s13244-016-0541-2 PICTORIAL REVIEW BUnforgettable^ – a pictorial essay on anatomy and pathology of the hippocampus Sven Dekeyzer 1,2,3 & Isabelle De Kock2 & Omid Nikoubashman1 & Stephanie Vanden Bossche 2 & Ruth Van Eetvelde2,3 & Jeroen De Groote2 & Marjan Acou2 & Martin Wiesmann1 & Karel Deblaere2 & Eric Achten2 Received: 19 September 2016 /Revised: 18 December 2016 /Accepted: 20 December 2016 # The Author(s) 2017. This article is published with open access at Springerlink.com Abstract • Clinical information is often necessary to come to a correct The hippocampus is a small but complex anatomical structure diagnosis or an apt differential. that plays an important role in spatial and episodic memory. The hippocampus can be affected by a wide range of congen- Keywords Hippocampus . Epilepsy . Dementia . Herpes ital variants and degenerative, inflammatory, vascular, tumoral simplex encephalitis . MRI and toxic-metabolic pathologies. Magnetic resonance imaging is the preferred imaging technique for evaluating the hippo- campus. The main indications requiring tailored imaging se- Abbreviations quences of the hippocampus are medically refractory epilepsy AD Alzheimer’sdementia and dementia. The purpose of this pictorial review is three- DNET Dysembryoblastic neuroepithelial tumour fold: (1) to review the normal anatomy of the hippocampus on IHI Incomplete hippocampal inversion MRI; (2) to discuss the optimal imaging strategy for the eval- HSE Herpes simplex encephalitis uation of the hippocampus; and (3) to present a pictorial over- LE Limbic encephalitis view of the most common anatomic variants and pathologic MTA Mesial temporal atrophy conditions affecting the hippocampus. MTS Mesial temporal sclerosis Teaching points • Knowledge of normal hippocampal anatomy helps recognize Anatomy, embryology, arterial supply and function anatomic variants and hippocampal pathology. • Refractory epilepsy and dementia are the main indications Normal hippocampal anatomy requiring dedicated hippocampal imaging. • Pathologic conditions centered in and around the hippocam- The hippocampus is a bilaminar gray matter structure lo- pus often have similar imaging features. cated medially in the temporal lobe that protrudes over the temporal horn of the lateral ventricle and occupies the me- dial region of its floor (Figs. 1 and 2). The hippocampus * Sven Dekeyzer consists of two interlocking gray matter folds, the cornu [email protected] ammonis (or hippocampus proper) and the dentate gyrus. In the axial plane, the hippocampus resembles a seahorse 1 Department of Diagnostic and Interventional Neuroradiology, (hence, its name) and it arches around the mesencephalon University Hospital, RWTH Aachen University, Pauwelsstr. 30, (hence, the term Bmesiotemporal^). In the axial and sagittal 52074 Aachen, Germany plane, it can be divided into three parts: (1) the head or 2 Department of Radiology, University Hospital (UZ) Ghent, De anterior segment; (2) the body or intermediate segment; Pintelaan 185, 9000 Ghent, Belgium and (3) the tail or posterior segment. White matter fibres 3 Department of Medical Imaging, Onze-Lieve-Vrouw Hospital (OLV) from the hippocampus accumulate on its superior surface Aalst, Moorselbaan 164, 9300 Aalst, Belgium to form the alveus. White matter fibres from the alveus Insights Imaging Fig. 1 Anatomy of the hippocampal formation on 3-T axial T2 (a)and sagittal 3D-MPRAGE images (b). Zoomed-in 3-T coronal T2-weighted images at the level of the hippocampal head (c) and the hippocampal tail Fig. 3 Arterial supply of the hippocampal body and tail. Orange = P1, (d). The hippocampal body is shown in detail in Fig. 2. 1 = hippocampal red = P2 and purple = P3 segment of the posterior cerebral artery. The head, 2 = hippocampal body, 3 = hippocampal tail, 4 = mesencephalon, anterior hippocampal artery is hidden in the uncal sulcus and is shown 5 = amygdala, 6 = hippocampal digitations, 7 = temporal horn of the in Fig. 4 lateral ventricle, 8 = uncal recess of the lateral ventricle, 9 = splenium of the corpus callosum, 10 = subsplenial gyri, 11 = crura of the fornices. To easily recognize the different portions of the hippocampus, we can use the mesencephalon (4). The head (1) is located in front of the Based on its cellular composition, the cornu ammonis is mesencephalon, the body (2) can be found at the level of the divided into four parts, the so-called Sommer’ssectorsCA1 mesencephalon and the tail (3) is posterior to the mesencephalon. The to CA4. The cornu ammonis continues inferomedially in the hippocampal head is the only portion of the hippocampus not covered by parahippocampal gyrus, a gray matter structure that forms the the choroid plexus (7). The hippocampal head is separated from the amygdala (5) by the uncal recess of the lateral ventricle (7) and is transition area between the basal and mesial areas of the tem- characterized by small digitations separated by small sulci, the poral lobe. The subiculum is the medial and superior edge of digitationes hippocampi (6). At the level of the hippocampal tail, the the parahippocampal gyrus and its site of union with the cornu fimbriae continue posteriorly as the crux of the fornix (11) that slants ammonis[1].The hippocampus is surrounded by several fis- upwards towards the splenium of the corpus callosum (9) and the hippocampal tail continues as the subsplenial gyri (10). sures which are collectively referred to as the perihippocampal fissures. The transverse fissure of Bichat is the lateral extension of the ambient cistern which separates the thalamus superiorly then gather medially into thickened bundles as the fimbria, from the parahippocampal gyrus inferiorly. The superolateral which are continuous posteriorly with the fornix [1]. extension of the transverse fissure is the choroidal fissure. The Fig. 2 Anatomy of the hippocampal formation at the level of the Ac = Ambient cistern, B = basal vein of Rosenthal, C = tail of caudate hippocampal body on 3-T coronal T2. The hippocampal formation nucleus, ChF = choroid fissure, CS = collateral suclus, DG = dentate consists of the cornu ammonis or hippocampus proper, which can gyrus, P = posterior cerebral artery, PHG = parahippocampal gyrus, histologically be divided in the four Sommer sectors CA1–CA4, and Sub = subiculum, T = temporal horn of the lateral ventricle, the dentate gyrus (DG). A small hippocampal cyst (Hs) reflects the Tb = transverse fissure of Bichat location of the largely obliterated hippocampal sulcus. A = alveus, Insights Imaging Fig. 6 Bilateral sulcal remnant cysts (a) and right-sided choroid fissure cyst (b, c). Coronal T2 shows small bilateral cysts at the apex of the hippocampal fold between the dentate gyrus and Ammon’s horn (a). Fig. 4 Arterial supply of the hippocampal head. B = basal Rosenthal Coronal FLAIR (b) and axial T2-weighted (c) images show a space- vein, 1 = temporal horn of the lateral ventricle, 2 = uncal recess of the occupying cystic lesion, iso-intense to cerebrospinal fluid, at the level lateral ventricle, 3 = hippocampal digitations, 4 = uncal sulcus. Both the of the right choroid fissure anterior hippocampal artery, originating from the trunk or branches of the posterior cerebral artery, and the uncal branch of the anterior choroidal plate along the medial wall and floor of the temporal horn artery, dive into the uncal sulcus at the level of the hippocampal head and (Fig. 5a). Gradual infolding of the various components occurs form anastomoses in the sulci between the hippocampal digitations. Here, only one of both arteries in the uncal sulcus is drawn as a result of expansion of the neocortex and unequal growth of the various hippocampal components (Fig. 5b, c). The inferolateral extension of the transverse fissure is the hippocam- infolding occurs around the hippocampal sulcus, a sulcus that pal fissure, which extends between the dentate gyrus and the develops between the dentate gyrus and cornu ammonis and subiculum and is often obliterated and not visible on MRI [1]. later shifts to a location between the dentate gyrus and subiculum (Fig. 5d). Eventually, the hippocampal sulcus be- Arterial supply of the hippocampus comes obliterated, but at times, a residual cavity, a so-called sulcal remnant cyst, may be seen (Fig. 6a). Usually, three arteries (or groups of arteries) arising from the main or branches of the posterior cerebral artery vascularize Function the hippocampus: the anterior, middle and posterior hippo- campal arteries. The anterior hippocampal artery supplies the The hippocampus plays an important role in spatial and episod- hippocampal head, whereas the middle and posterior hippo- ic memory. A possible role of the medial temporal lobe in campal arteries vascularize the hippocampal body and tail. memory formation was first suggested over a century ago by The middle and posterior hippocampal artery are richly inter- von Bechterew after presenting the neuropathological findings connected with another through the so-called longitudinal ter- from the brain of a 60-year-old man who had memory prob- minal segments that run parallel to the course of the hippo- lems during the last 20 years of his life and whose brain showed campal body (Fig. 3). The uncal branch of the anterior cho- bilateral softening of the gyrus uncinatus and the hippocampal roidal artery is usually anastomosed with the anterior hippo- formation [2]. The role of the hippocampus in episodic memory campal artery in the uncal sulcus (Fig. 4)[1]. became firmly established in 1957, when
Load more

Recommended publications
  • Anatomy of the Temporal Lobe
    Hindawi Publishing Corporation Epilepsy Research and Treatment Volume 2012, Article ID 176157, 12 pages doi:10.1155/2012/176157 Review Article AnatomyoftheTemporalLobe J. A. Kiernan Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON, Canada N6A 5C1 Correspondence should be addressed to J. A. Kiernan, [email protected] Received 6 October 2011; Accepted 3 December 2011 Academic Editor: Seyed M. Mirsattari Copyright © 2012 J. A. Kiernan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Only primates have temporal lobes, which are largest in man, accommodating 17% of the cerebral cortex and including areas with auditory, olfactory, vestibular, visual and linguistic functions. The hippocampal formation, on the medial side of the lobe, includes the parahippocampal gyrus, subiculum, hippocampus, dentate gyrus, and associated white matter, notably the fimbria, whose fibres continue into the fornix. The hippocampus is an inrolled gyrus that bulges into the temporal horn of the lateral ventricle. Association fibres connect all parts of the cerebral cortex with the parahippocampal gyrus and subiculum, which in turn project to the dentate gyrus. The largest efferent projection of the subiculum and hippocampus is through the fornix to the hypothalamus. The choroid fissure, alongside the fimbria, separates the temporal lobe from the optic tract, hypothalamus and midbrain. The amygdala comprises several nuclei on the medial aspect of the temporal lobe, mostly anterior the hippocampus and indenting the tip of the temporal horn. The amygdala receives input from the olfactory bulb and from association cortex for other modalities of sensation.
    [Show full text]
  • Toward a Common Terminology for the Gyri and Sulci of the Human Cerebral Cortex Hans Ten Donkelaar, Nathalie Tzourio-Mazoyer, Jürgen Mai
    Toward a Common Terminology for the Gyri and Sulci of the Human Cerebral Cortex Hans ten Donkelaar, Nathalie Tzourio-Mazoyer, Jürgen Mai To cite this version: Hans ten Donkelaar, Nathalie Tzourio-Mazoyer, Jürgen Mai. Toward a Common Terminology for the Gyri and Sulci of the Human Cerebral Cortex. Frontiers in Neuroanatomy, Frontiers, 2018, 12, pp.93. 10.3389/fnana.2018.00093. hal-01929541 HAL Id: hal-01929541 https://hal.archives-ouvertes.fr/hal-01929541 Submitted on 21 Nov 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. REVIEW published: 19 November 2018 doi: 10.3389/fnana.2018.00093 Toward a Common Terminology for the Gyri and Sulci of the Human Cerebral Cortex Hans J. ten Donkelaar 1*†, Nathalie Tzourio-Mazoyer 2† and Jürgen K. Mai 3† 1 Department of Neurology, Donders Center for Medical Neuroscience, Radboud University Medical Center, Nijmegen, Netherlands, 2 IMN Institut des Maladies Neurodégénératives UMR 5293, Université de Bordeaux, Bordeaux, France, 3 Institute for Anatomy, Heinrich Heine University, Düsseldorf, Germany The gyri and sulci of the human brain were defined by pioneers such as Louis-Pierre Gratiolet and Alexander Ecker, and extensified by, among others, Dejerine (1895) and von Economo and Koskinas (1925).
    [Show full text]
  • Multi-Contrast Submillimetric 3Tesla Hippocampal Subfield Segmentation
    www.nature.com/scientificdata OPEN Multi-contrast submillimetric SUBJECT CATEGORIES » Brain imaging 3Tesla hippocampal subfield » Magnetic resonance imaging segmentation protocol and dataset » Brain Jessie Kulaga-Yoskovitz1,*, Boris C. Bernhardt1,2,*, Seok-Jun Hong1, Tommaso Mansi3, » Neurology Kevin E. Liang1, Andre J.W. van der Kouwe4, Jonathan Smallwood5, Andrea Bernasconi1,* » Neuroscience & Neda Bernasconi1,* The hippocampus is composed of distinct anatomical subregions that participate in multiple cognitive processes and are differentially affected in prevalent neurological and psychiatric conditions. Advances in high-field MRI allow for the non-invasive identification of hippocampal substructure. These approaches, however, demand time-consuming manual segmentation that relies heavily on anatomical expertise. Here, Received: 10 August 2015 we share manual labels and associated high-resolution MRI data (MNI-HISUB25; submillimetric T1- and Accepted: 07 October 2015 T2-weighted images, detailed sequence information, and stereotaxic probabilistic anatomical maps) based Published: 10 November 2015 on 25 healthy subjects. Data were acquired on a widely available 3 Tesla MRI system using a 32 phased- array head coil. The protocol divided the hippocampal formation into three subregions: subicular complex, merged Cornu Ammonis 1, 2 and 3 (CA1-3) subfields, and CA4-dentate gyrus (CA4-DG). Segmentation was guided by consistent intensity and morphology characteristics of the densely myelinated molecular layer together with few geometry-based boundaries
    [Show full text]
  • Acetylcholinesterase Fiber Staining in the Human Hippocampus and Parahippocampal Gyrms
    THE JOURNAL OF COMPARATIVE NEUROLOGY 273:488-499 (1988) Acetylcholinesterase Fiber Staining in the Human Hippocampus and Parahippocampal Gyrms ROBERT C. GREEN AND M-MARSEL MESULAM Division of Neuroscience and Behavioral Neurology, Beth Israel Hospital and Harvard Medical School, Boston, Massachusetts 02215 ABSTRACT The AChE fiber distribution within the human hippocampus and para- hippocampal gyrus was studied in order to provide normative data for the examination of cholinergic fiberarchitecture in human pathology and to clarify the cytoarchitectonic organization of these structures. A modification of the Koelle method was used to stain temporal lobe serial sections from 6 neurologically normal human brains collected at autopsy. The hippocampal formation contains some ofthe densest staining of any cortical area. Regions with the heaviest concentrations of AChE fibers in- clude a thin band along the inner edge of the molecular layer of the dentate gyrus (ml-DG) and parts of the CA2, CA3, and CA4 sectors of Ammon's horn. Staining is of intermediate intensity in the CA1 region, The subiculum (S) is more lightly stained than the CA fields. Staining in the parahippocam- pal gyrus is generally less dense than in the hippocampal formation. The most conspicuous feature of the human entorhinal cortex (EC) is the AChE- rich fiber patches seen overlapping the stellate cell islands in layer 11. An additional band of relatively dense AChE staining is identified in layers N- V. Prominent AChE-rich polymorphic neurons are present within the hilum of the dentate gyrus. The CAlhubiculum transition in Nissl preparation is characterized by an oblique interdigitation of CA1 cells. The transition from EC to prorhinal cortex occurs along the medial bank of the rhinal sulcus and is characterized by a band of AChE staining, which slopes obliquely away from layer I1 until it joins an intermediate pyramidal cell layer.
    [Show full text]
  • Direct Visualization of the Perforant Pathway in the Human Brain with Ex Vivo Diffusion Tensor Imaging
    ORIGINAL RESEARCH ARTICLE published: 28 May 2010 HUMAN NEUROSCIENCE doi: 10.3389/fnhum.2010.00042 Direct visualization of the perforant pathway in the human brain with ex vivo diffusion tensor imaging Jean C. Augustinack1*, Karl Helmer1, Kristen E. Huber1, Sita Kakunoori1, Lilla Zöllei1,2 and Bruce Fischl1,2 1 Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA 2 Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA Edited by: Ex vivo magnetic resonance imaging yields high resolution images that reveal detailed cerebral Andreas Jeromin, Banyan Biomarkers, anatomy and explicit cytoarchitecture in the cerebral cortex, subcortical structures, and white USA matter in the human brain. Our data illustrate neuroanatomical correlates of limbic circuitry with Reviewed by: Konstantinos Arfanakis, Illinois Institute high resolution images at high field. In this report, we have studied ex vivo medial temporal of Technology, USA lobe samples in high resolution structural MRI and high resolution diffusion MRI. Structural and James Gee, University of Pennsylvania, diffusion MRIs were registered to each other and to histological sections stained for myelin for USA validation of the perforant pathway. We demonstrate probability maps and fiber tracking from Christopher Kroenke, Oregon Health and Science University, USA diffusion tensor data that allows the direct visualization of the perforant pathway. Although it *Correspondence: is not possible to validate the DTI data with invasive measures, results described here provide Jean Augustinack, Athinoula A. an additional line of evidence of the perforant pathway trajectory in the human brain and that Martinos Center for Biomedical the perforant pathway may cross the hippocampal sulcus.
    [Show full text]
  • Surgical Anatomy and Techniques
    SURGICAL ANATOMY AND TECHNIQUES MICROSURGICAL APPROACHES TO THE MEDIAL TEMPORAL REGION:AN ANATOMICAL STUDY Alvaro Campero, M.D. OBJECTIVE: To describe the surgical anatomy of the anterior, middle, and posterior Department of Neurological Surgery, portions of the medial temporal region and to present an anatomic-based classification University of Florida, of the approaches to this area. Gainesville, Florida METHODS: Twenty formalin-fixed, adult cadaveric specimens were studied. Ten brains Gustavo Tro´ccoli, M.D. provided measurements to compare different surgical strategies. Approaches were demon- Department of Neurological Surgery, strated using 10 silicon-injected cadaveric heads. Surgical cases were used to illustrate the Hospital “Dr. J. Penna,” results by the different approaches. Transverse lines at the level of the inferior choroidal point Bahı´a Blanca, Argentina and quadrigeminal plate were used to divide the medial temporal region into anterior, middle, and posterior portions. Surgical approaches to the medial temporal region were classified into Carolina Martins, M.D. four groups: superior, lateral, basal, and medial, based on the surface of the lobe through which Department of Neurological Surgery, University of Florida, the approach was directed. The approaches through the medial group were subdivided further Gainesville, Florida into an anterior approach, the transsylvian transcisternal approach, and two posterior ap- proaches, the occipital interhemispheric and supracerebellar transtentorial approaches. Juan C. Fernandez-Miranda, M.D. RESULTS: The anterior portion of the medial temporal region can be reached through Department of Neurological Surgery, University of Florida, the superior, lateral, and basal surfaces of the lobe and the anterior variant of the Gainesville, Florida approach through the medial surface.
    [Show full text]
  • Transsulcal Approach to Mesiotemporal Lesions
    Transsulcal approach to mesiotemporal lesions Anatomy, technique, and report of three cases Isabelle M. Germano, M.D. Department of Neurosurgery, Mount Sinai School of Medicine, New York, New York Surgical resection of mesiotemporal lesions, particularly those in the dominant hemisphere, is often challenging. Standard approaches require excessive brain retraction, removal of normal cortex, or manipulation of the middle cerebral artery branches. This report describes a transsulcal temporal approach to mesiotemporal lesions and its application in three patients. Gross-total resection of the lesion was accomplished in all cases. An anatomical cadaveric study was also performed to delineate the microsurgical anatomy of this approach. Precise knowledge of temporal intraventricular landmarks allows navigation to the lesion without the need for a navigational system. This approach is helpful for neurologically intact patients with mesiotemporal lesions. Key Words * temporal lobe * seizure * brain tumor * cavernous angioma * surgical approach In patients with temporal lobe epilepsy, surgical resection of a lesion in the temporal lobe, "lesionectomy," has been shown to provide successful seizure control for different pathologies;[1,2] however, gaining access to the mesiotemporal lobe lesions while preserving the surrounding normal structures is often challenging. Although several approaches to the amygdala and hippocampus have been described in the literature on surgery for epilepsy, they all require sacrifice of normal structures, manipulation of arteries, or excessive temporal lobe retraction. Here, the author describes a transsulcal approach for mesiotemporal lesions that requires no resection of normal structures and minimal retraction. Three cases in which this technique was used are presented. OPERATIVE TECHNIQUE The rationale for using this technique is that the superior and middle temporal sulci provide the most direct pathway to the mesiotemporal area.
    [Show full text]
  • Transsulcal Approach to Mesiotemporal Lesions
    Transsulcal approach to mesiotemporal lesions Anatomy, technique, and report of three cases Isabelle M. Germano, M.D. Department of Neurosurgery, Mount Sinai School of Medicine, New York, New York Surgical resection of mesiotemporal lesions, particularly those in the dominant hemisphere, is often challenging. Standard approaches require excessive brain retraction, removal of normal cortex, or manipulation of the middle cerebral artery branches. This report describes a transsulcal temporal approach to mesiotemporal lesions and its application in three patients. Gross-total resection of the lesion was accomplished in all cases. An anatomical cadaveric study was also performed to delineate the microsurgical anatomy of this approach. Precise knowledge of temporal intraventricular landmarks allows navigation to the lesion without the need for a navigational system. This approach is helpful for neurologically intact patients with mesiotemporal lesions. Key Words * temporal lobe * seizure * brain tumor * cavernous angioma * surgical approach In patients with temporal lobe epilepsy, surgical resection of a lesion in the temporal lobe, "lesionectomy," has been shown to provide successful seizure control for different pathologies;[1,2] however, gaining access to the mesiotemporal lobe lesions while preserving the surrounding normal structures is often challenging. Although several approaches to the amygdala and hippocampus have been described in the literature on surgery for epilepsy, they all require sacrifice of normal structures, manipulation of arteries, or excessive temporal lobe retraction. Here, the author describes a transsulcal approach for mesiotemporal lesions that requires no resection of normal structures and minimal retraction. Three cases in which this technique was used are presented. OPERATIVE TECHNIQUE The rationale for using this technique is that the superior and middle temporal sulci provide the most direct pathway to the mesiotemporal area.
    [Show full text]
  • Anatomical Variations of the Dentate Gyrus in Normal Adult Brain
    Uniwersytet Medyczny w Łodzi Medical University of Lodz https://publicum.umed.lodz.pl Anatomical variations of the dentate gyrus in normal adult brain, Publikacja / Publication Haładaj Robert Zbigniew DOI wersji wydawcy / Published http://dx.doi.org/10.1007/s00276-019-02298-5 version DOI Adres publikacji w Repozytorium URL / Publication address in https://publicum.umed.lodz.pl/info/article/AMLb93a6e8ff4b44947bc0c42d5615d0280/ Repository Data opublikowania w Repozytorium 2020-01-08 / Deposited in Repository on Rodzaj licencji / Type of licence Attribution (CC BY) Haładaj Robert Zbigniew: Anatomical variations of the dentate gyrus in normal adult Cytuj tę wersję / Cite this version brain, Surgical and Radiologic Anatomy, vol. 42, no. 2, 2020, pp. 193-199, DOI: 10.1007/s00276-019-02298-5 Surgical and Radiologic Anatomy https://doi.org/10.1007/s00276-019-02298-5 ORIGINAL ARTICLE Anatomical variations of the dentate gyrus in normal adult brain Robert Haładaj1 Received: 20 June 2019 / Accepted: 26 July 2019 © The Author(s) 2019 Abstract Recent scientifc papers indicate the clinical signifcance of the dentate gyrus. However, a detailed knowledge of the ana- tomical variations of this structure in normal adult brain is still lacking. An understanding of the variable morphology of the dentate gyrus may be important for diagnostic neuroimaging. Thus, the purpose of this macroscopic cadaveric study was to describe the anatomical variations of the dentate gyrus. Forty formalin-fxed human cerebral hemispheres, obtained from bodies of donors without the history of neuropathological diseases, were included in the study. The dentate gyrus was classifed as well-developed, when it protruded completely from under the fmbria of the hippocampus.
    [Show full text]
  • Figures 1-29 for Dalton Et Al. Brain and Neuroscience Advances
    a Dorsal b Dorsal c Dorsal * * * * * * * Medial * Lateral Medial * * Lateral Medial Lateral Ventral Ventral Ventral d CA2 e f Fimbria CA3 CA2 CA3 Uncus Fimbria CA4 Fimbria CA1 Uncus CA4 CA1 Uncus CA3/2 DG DG DG/CA4 CA1 Pre/ parasubiculum Prosubiculum/ Prosubiculum/ subiculum Pre/parasubiculum Pre/parasubiculum Prosubiculum/ subiculum subiculum Subregions Important Landmarks DG/CA4 CA3/2 Vestigial Hippocampal Sulcus (VHS) Uncus CA1 Fimbria / Dorsal Wall of the Hippocampus Prosubiculum/subiculum * - Islands Indicating Presubiculum Pre/parasubiculum Uncus Figure 1 Figure 2 Dorsal a b c d e f Posterior Medial Lateral DG/CA4 CA1 Pre/parasub Anterior CA3/2 Prosub/sub Uncus Ventral Figure 3 Legend Subregions US - Uncul Sulcus a DG/CA4 VHS - Vestigial Hippocampal Sulcus > - Dorsal Extent of VHS CA3/2 ^ - Ventral Extent of VHS CA1 * - Islands indicating Presubiculum Prosubiculum/subiculum % - Fimbria # - Dorsolateral Extent of Lateral Uncul Sulcus / Pre/parasubiculum Ventromedial Extent of the Fimbria Uncus ! Medial Extent of the Lateral External Digitation Vestigial Hippocampal Sulcus b Dorsal c Dorsal d Dorsal 7 7 7 6 6 ! ! 6 ! Medial Lateral Medial Lateral Medial Lateral 2 2 2 Ventral Ventral Ventral e f g Lateral External Digitation 7 Lateral External Digitation 6 4 5 Figure 4 Legend Subregions US - Uncul Sulcus a DG/CA4 VHS - Vestigial Hippocampal Sulcus > - Dorsal Extent of VHS CA3/2 ^ - Ventral Extent of VHS CA1 * - Islands indicating Presubiculum Prosubiculum/subiculum % - Fimbria # - Dorsolateral Extent of Lateral Uncul Sulcus / Pre/parasubiculum
    [Show full text]
  • HIPPOCAMPUS and SEPTUM
    HIPPOCAMPUS and SEPTUM From Hendelman, 2000 1-rhinal sulcus; 2-collateral sulcus; 3-intrrhinal sulcus; 4-occipitotemoral sulcus; 5-gyrus ambiens; 6-entorhinal ctx; 7-perirhinal ctx, anterior portion; 8-uncus; 9-hippocampal fissure; 10-s. semiannularis; 12- mammillary bodies; 17-optic chisam; 18-olfactory tract; 19-olf. Bulb; 20-substantia nigra; 22-corpus callosum (splenium); 23- choroidal fissure; 25-parahippocampal gyrus (From Insausti and Amaral, 2004) Monkey-From Amaral Human: G. van Hoesen TF 1-rhinal sulcus; 2-collateral sulcus; 3-intrrhinal sulcus; 5-gyrus ambiens; 6-entorhinal ctx; 8-uncus; 9-hippocampal fissure; 10-sulcus semiannularis; 11-gyrus semilunaris;12- mammillary bodies; 13-anterior commissure; 14-precommissural fornix; 15- postcommissural fornix;16thalamus; 21 corpus callosum rostrum; 22 corpus callosum AB Median sagittal surface of the human (A , B,) brain. A: Sobotta, B: Broadmann; C: Roland, In (C) the scheme is C drawn in the Talairach coordinates. D CS-collateral sulcus; FM fimbria; GS-semilunar gyrus; POC-primary olfactory cortex; RS- rhinal sulcus; SS-sulcus semianularis; TN-tentorial notch; UHF-uncal hippocampal formation; CF calcarine fissure; HIP hippocampus; ITG inferior temporal gyrus; OT olfactory tract; PHG- parahippocampal gyrus; TP-temporal pole: 28- atrophic entorhinal area (From G vanHoesen) From Handelman, 2000 From Handelman, 2000 Neuwenhys Medial Temporal Lobe. Amygdala and hippocampus From Amaral Amaral fusiform gyrus From Amaral VI ectorhinal ctx area 36 Parahippocampal gyrus (cortex): anterior part (entorhinal cortex and associated perirhinal cortex (areas 35,36); posterior part that includes TF and TH of von Economo. 12 week 8mm sl A: midsagittal, B: horizontal; C-D medial wall of the telencephalon to show how the dentate gyrus (DG) and the Ammons’s horn (AH)may fold during progressively later stages to assume the shape illustrated in the subsequent figure.
    [Show full text]
  • Surgical Anatomy of the Hippocampus
    Neurochirurgie 59 (2013) 149–158 Disponible en ligne sur ScienceDirect www.sciencedirect.com Update Surgical anatomy of the hippocampus Anatomie chirurgicale de l’hippocampe a,∗,b,c d a,b,c C. Destrieux , D. Bourry , S. Velut a Laboratoire d’anatomie, université Franc¸ ois-Rabelais de Tours, 10, boulevard Tonnellé, 37032 Tours cedex, France b Inserm U930, UMR « imagerie et cerveau », université Franc¸ ois-Rabelais de Tours, 37032 Tours, France c Service de neurochirurgie, CHRU de Tours, 37044 Tours, France d UFR médecine, département communication et multimédias, université Franc¸ ois-Rabelais de Tours, 37032 Tours, France a r t i c l e i n f o a b s t r a c t Article history: Background and purpose. – Hippocampectomy is an efficient procedure for medial temporal lobe epilepsy. Received 16 March 2013 Nevertheless, hippocampus anatomy is complex, due to a deep location, and a complex structure. In this Accepted 6 August 2013 didactic paper, we propose a description of the hippocampus that should help neurosurgeons to feel at ease in this region. Keywords: Methods. – Embryological data was obtained from the literature, whereas adult anatomy was described Hippocampus after dissecting 8 human hemispheres (with and without vascular injection) and slicing 3 additional ones. Anatomy Results. – The hippocampus is C-shaped and made of 2 rolled-up laminae, the cornu Ammonis and the Epilepsy surgery gyrus dentatus. Its ventricular aspect is covered by the choroid plexus of the inferior horn excepted at the head level. Its cisternal aspect faces the mesencephalon from which it is limited by the transverse fissure.
    [Show full text]