Windows to the Brain: Introduction to Neuroanatomy
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VA Mid-Atlantic Health Care Network Windows to the Brain: Introduction to Neuroanatomy Overview Planes of Section Radiographic Perspective Major Divisions Cortical Lobes, Gyri & Sulci General Functions Brodmann’s Areas Basal Forebrain Subcortical Structures Symptoms Cerebellum Structures Symptoms Katherine Taber, PhD, FANPA MIRECC Assistant Director - Education Research Health Scientist W.G. “Bill” Hefner VAMC, Salisbury NC Research Professor, Div Biomedical Sciences Edward Via College of Osteopathic Medicine Robin Hurley, MD, FANPA MIRECC Associate Director - Education ACOS/Research and Academic Affairs Service Line W.G. “Bill” Hefner VAMC, Salisbury NC Professor, Psychiatry and Radiology Wake Forest School of Medicine revised September 2019 Source: http://www.mirecc.va.gov/visn6/Tools-Tips.asp Use of text, images and other content are subject to the following terms and conditions: Fair Use Is Permitted Fair use of copyrighted material includes the use for non-commercial educational purposes, such as teaching, scholarship, research, criticism, commentary, news reporting, and other content. Unless otherwise noted, users who wish to download or print text and image files from this Web site for such uses may do so without the VISN 6 MIRECC’s express permission, provided that they comply with the following conditions: The content may only be used for personal, educational or non- commercial purposes; Users must always specifically cite the author(s) and source of the content every time the material is used, as they would for material from any printed work; None of the content may be altered or modified. Warranty By downloading, printing, or otherwise using text and image files from this website, users agree and warrant that they will limit their use of such files to fair use. 1 Planes of Section In medical practice the most Lateral View common way to view the brain is Superior the two dimensional sections r r o i provided by magnetic resonance o i r r axial plane of section e e imaging (MRI) and computed t t s n tomography (CT). While it is o A possible to image the brain in P virtually any orientation, the axial coronal plane of section plane of section is used most often as it allows the entire brain to be captured in the fewest number of sections. Anatomists Inferior prefer the coronal plane of section because many structures, Inferior (Bottom) View particularly small ones, are more easily recognized. Note that both r r o the axial and sagittal planes of i o sagittal plane of section i r r section go from the front (anterior) e e t t s n to the back (posterior) of the brain. o A Axial goes from one side to the P Medial other (medial to lateral). Sagittal goes from top (superior) to bottom (inferior). coronal plane of section Lateral axial plane of section sagittal plane of section coronal plane of section 2 Radiographic Perspective Clinical images are displayed in the radiographic perspective. Most teaching and reference materials use the anatomic perspective. All radiographic images are displayed using a single set of conventions: patient is lying on his/her back (supine) patient’s patient’s right left viewer is at patient’s feet looking toward the patient’s head viewer There are 2 key differences between the radiographic perspective and the anatomic perspective that are important to remember when viewing clinical brain images. [1] The left side of an axial or coronal brain image is the right side of the brain: R L R L patient’s patient’s right left viewer [2] On axial images brainstem and spinal cord will be inverted compared to how they are displayed in most teaching and reference materials: 3 Major Divisions Major Divisions The neural tube (illustrated in schematic form) expands locally to form the 3 primary divisions or vesicles: forebrain (prosencephalon, yellow), midbrain (mesencephalon, green), and hindbrain (rhombencephalon, purple). These in turn form the 5 secondary divisions. The forebrain vesicle subdivides into telencephalon (yellow) and diencephalon (light green). The hindbrain vesicle subdivides into the metencephalon (blue) and myelencephalon (pink). * Primary Secondary Final Areas Formed Divisions Divisions forebrain telencephalon cerebral hemispheres, limbic system, (prosencephalon) basal ganglia diencephalon thalamus, hypothalamus, epithalamus, midbrain subthalamus, optic vesicle (mesencephalon) mesencephalon superior & inferior colliculi, red nucleus, hindbrain substantia nigra, periaqueductal gray (rhombencephalon) metencephalon pons, cerebellum myelencephalon medulla spinal cord spinal cord z Inferior (Bottom) View The 5 secondary divisions are color-coded onto magnetic resonance images to provide cerebral cortex overall orientation. pons medulla cerebellum Midline Medial (Parasagittal) View Lateral View cerebral cortex cerebral cortex corpus callosum diencephalon midbrain pons cerebellum pons cerebellum medulla medulla *Taber KH, Salpekar J, Wong AHC, Hurley RA. J Neuropsychiatry Clin Neurosci 2011;23(1): 1-5. 4 Cerebral Cortex - Lobes Midline Medial (Parasagittal) View Lateral View parietal frontal parietal limbic frontal occipital occipital temporal parietal frontal limbic parietal frontal occipital occipital temporal temporal Medial Orbital Inferior (Bottom) View The highly in-folded cerebral cortex is the largest single division of the temporal human brain. Anatomists commonly occipital divide it into four sections or lobes - frontal the frontal, temporal, parietal and limbic occipital lobes. Some consider the limbic areas of cortex to comprise a fifth lobe, whereas others include these areas in the frontal and temporal lobes and diencephalon. Note that the medial and posterior inferior surfaces of the temporal lobe Lateral can only be seen on the drawings of temporal the medial and inferior surfaces of the brain. This is because the brainstem frontal occipital and cerebellum have been omitted on limbic the drawings. Medial parietal 5 Major Gyri & Sulci Midline Medial (Parasagittal) View Lateral View Central Central (Rolandic) Sulcus l (Rolandic) a r l Sulcus t a n tr S Paracentral P Parietooccipital al e u re nt c n p lobule cu Sulcus o l e e P e n r ta r tc a ri l e F n P s r o nta us r o L ie r ro o r o ob ta F ri F P u l r Cingulate e e A le io Calcarine l r p d ma n u r ra r g e Sulcus id o p g u S l u i p Cuneus i n r S l u M ta Subcentral a a e l r S f n al n o r I r po Lin F em l Occipital gua r T ra l rio po pe m l Su Te ra Gyrus Rectus Orbital dle po id Tem M or eri Inf SylvOiarnbiFtiasslure (Lateral Sulcus) Central Central (Rolandic) Sulcus (Rolandic) Sulcus l Paracentral l a l tal ta r P S on lobule Pr Parietooccipital n t ra a up r ec ro n t ri e F u Sulcus F l e n et r r ne r ta c e a io io Cingulate u o n e c A l r r s i ro r t ng Lo e r F P s u b e o la u p p le P r le u Calcarine u ma Subcallosal d r ra r S S d p g Cuneus Sulcus o u i i l n (Paraolfactory) i S r a a t l Area M e Hippocampus f n Subcentral l Occipital In o ra al r po Uncus p Lin F m am gu r Te l poc al rio ora arahip pe p Gyrus Rectus P m Su Tem usifor l le ral F ora dd mpo mp Mi r Te Inferior Te Sylvian Fissure ferio (Lateral Sulcus) In frontal temporal parietal occipital limbic Inferior (Bottom) View Posterior Orbital ral al po Later Tem bital rior Or Infe Anterior form An outfolding of the cerebral Orbital Fusi Medial Orbital cortex is called a gyrus Parahippocampal Gyrus Rectus (plural is gyri), an infolding is Uncus called a sulcus (plural is sulci). Some very large sulci are called fissures. Although major gyri and sulci are present in all normal brains, Sylvian Fissure they can vary considerably in (Lateral Sulcus) Inf erior both extent and location. Temp al Fu ora Lateral Later sifo l tal rm Many areas have Orbi considerable normal AnteriorPosterior rahippo Orbital Orbital Pa cam pa variation in the folding Medial Orbital Uncus l patterns. Gyrus Rectus Medial 7 Major Functions Right Hemisphere Medial (Parasagittal) View Lateral View Somatosensory Motor Initiation Motor Hip & Synchronization Sensory Somatosensory Initiation of Speech Integration & Arm & Synchronization Leg & Complex Focused Attention, Recognition Hand of Speech Movements N onverbal Intellect & Complex Sensory Integration & Foot & N onverbal Hand Movements Memory Recognition Audiovisual Focused Attention, Management Awareness & Face Deficit Recognition N onverbal Intellect Visual Face & N onverbal Orientation, Music & Voice Tongue Speech Memory Recognition Prosody & Guidance & Hearing Management Scanning Gesturing Visuospacial Smell Social Conduct, Recognition Visuospacial Insight & Seeing N aming Recognition Judgment N aming Visual Orientation, Social Conduct, Seeing, Color Vision, Guidance & Scanning Insight & Judgment & W hole Object Imaging Inferior (Bottom) View Right Hemisphere - In most Retrograde Lateral N am individuals, the processing of Visuospacial Episodic ing nonverbal information, such as Recognition Memory N onverbal Social Seeing, Conduct, music or visuospatial information, Color Vision, Memory & Emotion Insight & occurs primarily in the right & Smell W hole Object Judgment hemisphere. Imaging frontal temporal parietal occipital limbic Medial Left Hemisphere Medial (Parasagittal) View Lateral View Motor Somatosensory Motor Hip Focused Initiation & Somatosensory Initiation & Attention, Synchronization Synchronization Arm of Speech Leg of Speech Sensory Integration Verbal Intellect Leg Hand & Verbal & Complex & Complex & Recognition S Foot m Movement Foot Sensory Integration V o Movement Memory P i o Hand g u su t Hand in