Brain Gross Anatomy PDF

Brain Gross anatomy Fortunato Battaglia, MD PhD  Objectives: 1. Describe the general organization and the major anatomical structures of the central nervous system. 2. Identify major lobes of the brain and the fissures which separate them. 3. Identify some of the more important gyri and sulc...

Brain Gross anatomy Fortunato Battaglia, MD PhD  Objectives: 1. Describe the general organization and the major anatomical structures of the central nervous system. 2. Identify major lobes of the brain and the fissures which separate them. 3. Identify some of the more important gyri and sulci. 4. Discuss the functions of the different lobes. 5. Explain the arrangement of gray and white matter. 6. Describe the vessels that supply the CNS. 7. Describe anatomy and function of the choroid plexus. 8. Trace circulation of cerebral spinal fluid. 9. Explain role of cerebral spinal fluid in both normal and pathological conditions. 10. Describe the internal carotid arterial system to the brain, the major branches and what structures they supply. 11. Describe the vertebral-basilar arterial system to the brain, its major branches and what structures they supply. 12. Explain how somatotopy relates to blood supply occlusions, if applicable. 13. Describe the Circle of Willis and how it connects the internal carotid and vertebral-basilar systems. 14. Explain blood supply syndromes. 15. Describe the venous drainage of the brain and the major sinuses involved in this drainage. 16. Explain the structure of the blood brain barrier and why it is important.  Orientation in the CNS Planes of Orientation: {C}}vo {H}]}vo {SP]o Directions: {Co t Rostral {D}o - Ventral {S]} - Inferior {Av]} - Posterior  Gross Anatomy of the CNS Surface Anatomy: {G˙AA]P {SoAAP}}`v]P {F]AAo~Z(]}(S˙o][ Brain: Brainstem: Spinal Cord: { Forebrain {M]]v {C]o - telencephalon {H]v]v {TZ}] - cerebrum - medulla {Lu - basal ganglia - pons {So - diencephalon - cerebellum - thalamus - hypothalamus - subthalamus The Lateral Surface Central Sulcus Parietal Lobe Frontal Lobe Occipital Lobe Lateral Sulcus Temporal Lobe (Sylvian Fissure) The Lateral Surface Precentral Gyrus, Primary Motor Cortex Central Sulcus Precentral Sulcus 1 2 Frontal Pole OP TRI Broca’s Area 3 OR Lateral Sulcus (Sylvian Fissure) The Lateral Surface Postcentral Gyrus Central Sulcus (Primary Somatosensory Cortex) Postcentral Sulcus Intraparietal Sulcus Superior Parietal Lobule Inferior Parietal Lobule (Primary Vestibular Cortex) Lateral Sulcus (Sylvian Fissure) The Lateral Surface Occipital Pole, Primary Visual Cortex The Lateral Surface Heschl’s Gyri (Primary Auditory Cortex) Wernicke’sArea Superior Superior Temporal Temporal Temporal Pole Gyrus Sulcus Frontal Eye Fields (FEF) Insula lobe Surface Anatomy of the Forebrain Lobes: Frontal, Parietal ,Occipital, Temporal, Limbic a) Major Sulci & Gyri Longitudinal fissure - separates the 2 cerebral hemispheres Central sulcus - separates frontal and parietal lobes Lateral fissure - separates frontal and parietal lobes from temporal lobe Parieto-occipital sulcus - on medial surface, separates occipital lobe from parietal / temporal lobes Calcarine fissure - on medial surface in occipital lobe Precentral gyrus - anterior to central sulcus - primary motor area Postcentral gyrus - posterior to central sulcus - primary somatosensory area Lateral-medial structures Inferior-ventral structures Ventral surface Olfactory Fissure OR Gyrus Rectus Primary Olfactory Uncus Cortex Rhinal fissure Fusiform Gyrus (facial recognition) Parahippocampal Gyrus (Memory) Mid-Sagittal Surface Central Sulcus Pa racentral s gyru L o b ule l n ta Cingulate Sulcus fro r io er Cingulate Gyrus Sup rpus Callosum CoBody Genu Splenium Rostrum Callosal Sulcus Frontal lobe t functional anatomy I. Precentral Gyrus (Primary Motor Cortex): Function: Control of voluntary muscle movements throughout the body. II. Premotor Cortex: Function: Planning and coordination of complex, coordinated movements; also involved in motor learning. III. Broca's Area (Left Hemisphere): Function: Language production and speech formation. IV. Prefrontal Cortex: Function: higher-order cognitive functions, including: Executive functions (e.g., decision-making, planning, problem-solving). Emotional regulation. Social behavior and judgment. Personality expression and control. Working memory. V. Orbitofrontal Cortex: Function: emotional processing, decision-making, and social behavior. VI. Dorsolateral Prefrontal Cortex: Function: working memory, cognitive flexibility, and goal-directed behavior. VII. Frontal Eye Fields: Function: Control of voluntary eye movements, particularly saccades VIII. Anterior Cingulate Cortex: Function: motivation, error detection, and decision-making. IX. Motor Association Cortex: Function: Coordination and planning of complex motor actions, integrating sensory information to guide movements. X. Supplementary Motor Area (SMA): Function: Involved in planning and coordinating complex motor actions, especially those involving sequences of movements. Parietal lobe functional anatomy I. Primary Somatosensory Cortex: Location: Postcentral gyrus, located just posterior to the central sulcus. Function: Processes sensory information related to touch, pressure, temperature, and pain from all over the body. II. Somatosensory Association Cortex: Location: Located adjacent to the primary somatosensory cortex. Function: Integrates sensory information III. Supramarginal Gyrus: Location: Located near the lateral sulcus. Function: Involved in language processing, particularly phonological processing (speech sounds) and reading. IV. Angular Gyrus: Location: Adjacent to the supramarginal gyrus and near the posterior part of the lateral sulcus. Function: Associated with language processing and reading comprehension, as well as cross-modal integration of sensory information. Temporal lobe Temporal lobe functional anatomy I. Primary Auditory Cortex (Heschl's Gyrus): Location: Located within the superior temporal gyrus. Function: Processes auditory information, including sound perception and discrimination. II. Wernicke's Area (Left Hemisphere): Location: Typically found in the left posterior superior temporal gyrus. Function: Critical for language comprehension and formulation of coherent speech. III. Hippocampus: Location: Deep within the temporal lobe, part of the limbic system. Function: Involved in the formation of new memories and spatial navigation. IV. Parahippocampal Gyrus: Location: Surrounds the hippocampus. Function: Plays a role in memory formation, spatial processing, and scene recognition. V. Fusiform Face Area (FFA): Location: Found in the ventral part of the temporal lobe. Function: Specialized for facial recognition and processing. VI. Inferior Temporal Cortex: Location: Adjacent to the fusiform face area. Function: Involved in object recognition, including the recognition of complex visual stimuli. VII. Middle Temporal Gyrus: Location: Positioned between the superior and inferior temporal gyri. Function: Associated with various functions, including language processing, visual motion perception, and attention. VIII. Superior Temporal Gyrus: Location: Runs along the superior aspect of the temporal lobe. Function: Involved in higher-level auditory processing, including language processing and sound localization. Diencephalon  Deep Structures of the Forebrain Diencephalon (everything with ZZou[]vZvu {TZou - gatekeeper to the cerebral cortex - 2 thalami, egg- Pineal gland shaped masses of gray matter that border the 3rd ventricle {H˙}Zou - located under the thalamus - involved in control of autonomic and endocrine function - influences emotional and motivational aspects of behaviour {SZou - located inferior and lateral to the thalamus - involved in modulation of voluntary motor activity  Gray Matter vs. White Matter Gray Matter: {`ZZvoo}] reside - cortical layer - deep nuclei White Matter: {`ZZ(] (axons) reside - connect different parts of the CNS - run in all directions and intermingle with each other - most fibers are myelinated  Commissural pathways Corpus Parts: Rostrum, Genu, Body, and callosum splenium Function: Connects corresponding regions of almost all parts of the cerebral cortex of the two hemispheres Anterior Parts: Anterior and posterior commissure bundle Function: Connects structures of the olfactory pathway, the frontal cortex, temporal pole and parahippocampal gyri Posterior Function: Connects the commissure language processing centers of both cerebral hemispheres Brainstem Cranial nerves  Cerebral Meninges 1. Dura mater (2 layers) - Outer: serves as periosteum of inner surface of skull - Inner: the meningeal dura 2. Arachnoid mater - thinner middle layer, lines the dura, bridges over sulci - in life, the subarachnoid space contains cerebrospinal fluid 3. Pia mater - thin, delicate innermost layer - adheres tightly to surface of brain, following all gyri and sulci  Dura m a t e r o u t e rl a y e r Superior sagittal sinus i n n e r layer Aarchnodi Skull m erat P i am a t e r Meninges Schematic, Coronal Section Reflections of the Dura {Fo˘] {Fo˘oo] {Tv}]uoo] { Diaphragma sellae talx cere bri t e n t o r i u m cerebelli Meningeal Spaces (between the meningeal layers) {E]olE˘o space {So {SZv}]  Ventricular System and Cerebrospinal Fluid (CSF) {TZv]o]]`]Z]vZCNSX {}]vo C (o]~CSF]}˙ZZ}}]o˘v]o within the ventricles. {TZo}vvZvZv]oX {Zv]o]}v]v}`]ZZvovo}(Z]vo}X {Ovu]o]v~MPv]v`}oo~LZl(}u]voo}`CSF} flow into the subarachnoid space. Lateral ventricles (one in each cerebral hemisphere) o Body o Anterior horn o Posterior horn o Inferior horn 3rd ventricle (midline cavity between halves of the diencephalon) Interventricular foramen (foramen of Monro - connects each lateral ventricle with the 3rd ventricle) 4th ventricle (in the pons and medulla) The cerebral aqueduct (queduct of Sylvius- connects the 3rd ventricle with the 4th ventricle)  Circulation of Cerebrospinal Fluid (CSF) {CSF]˙Z]Zo]u}(ZZ}}]o˘U`Z]Z](}v]voov]oXTZ ventricles are lined with ependymal cells. At certain locations, the ependyma-pia complex invaginates into the ventricles together with capillaries traveling in the subarachnoid space. Here the ependymal layer becomes a cuboidal epithelium, the choroid epithelium, and is secretory. {CSFu}(}uZooU}ZU}ZZv]oUZo}vP˙v`o˙(}uCSFX {CSF(o}`]v}Zvovo}(Z]vo}Uv(o}`}}(ZZv]oZ}PZZ 2 lateral foramina (Luschka) and 1 central foramen (Magendie) and into the subarachnoid space. {CSFu}Z}PZZZv}]v]o]ZZZv}]Pvo]}v}]oo] which protrude primarily into the superior sagittal sinus. {M}uv}ZZv}]]oo]]]U]v˙Z]((v]vZ˙}] between the CSF in the subarachnoid space and the venous blood in the superior sagittal sinus. The villi act like tiny flap valves so reverse flow is prevented if venous pressure exceeds CSF pressure. {SZv}]]vWZ`]Z}(ZZv}]]}(Z]Po contours of the brain. Regions that contain more substantial amounts of CSF are called subarachnoid cisterns. Superior sagittal sinus Arachnoid granulation Subarachnoid space Meningeal dura mater Choroid plexus Right lateral ventricle Interventricular foramen Third ventricle Cerebral aqueduct Lateral aperture - Median aperture Fourth ventricle - Central canal 1) CSF production = 20ml/hour 2) CSF amount = 125-150ml 3) Normal opening pressure = 6-20 cm H20 (up to 25 fi obese) Subarachnoid Cisterns  Inferior sagittal sinus Superior sagittal sinus Straight sinus Confluence of the sinuses Transverse sinus Sigmoid sinus Internal jugular vein Vascular system Arterial Supply of the Brain  Supply C e r e b r a la r t e r y Group 1. Anterior cerebral artery Middle cerebral artery Internal carotid 3. Anterior choroidal artery Anterior c i r c u l a t i o n Posterior communicating artery Poste rior cere bral a r t e r y Posterior cerebral artery Superior cerebellar a r t e r y Vertebral/Basilar :7 Anterior inferior cerebellar artery Posterior circulation Posterior inferior cerebellar artery Ante rior spin al a r t e r y 10. Posterior spinal artery Internal Carotid Artery (ICA) Internal Carotid Artery Common Carotid Artery Off Brachiocephalic Trunk - Right Off Arch of Aorta - Left S u b c l a v i a n Ar ter y Carotid Bifurcation C2 C3 Internal carotid artery Common carotid artery) Normally at superior border of thyroid cartilage = C, Vertebra Internal carotid artery Cervical part ("pars cervicalis") Petrous part ("pars petrosa") Cavernous part ("pars cavernosa") Cerebral part ("parts cerebralis") ICA B r a n c h e s /Anterior Cerebral A. Middle Cerebral A. ICA Post. Comm. Artery Anterior Choro idal Artery ICA B r a n c h e s Ophthalmic Artery Anterior Cerebral Artery ICA Middle Cerebral Artery Anterior Choroidal Artery Post erio r Communicating Artery Ophthalmic artery (ICA) Anterior Cerebral Artery (ACA) Anterior Cerebral Artery ACA Anterior Cerebral Artery ACA = pink Middle cerebral artery Middle Cerebral Artery ACA Middle Cerebral A. My segment  Middle cerebral artery components M1 M2 M3 M4 MCA: M1, M2, M3 M3: superior and inferior divisions MCA: superior and inferior divisions Middle Cerebral Artery MCA = green Basal ganglia territory  (Recurrent artery of Heubner) Lenticulostriate arteries  Lateral ACA ventricle Caudate MCA superior division MCA inferior divisi on MCA deep branches PCA Anterior PCA deep choroi dal branches artery © 202 Sniauer Associates, Inc Coronal s e c t i o n Anterior choroidal artery Anterior choroidal artery Posterior limb of the internal capsule, the optic tract, and the lateral geniculate nucleus , the medial segment of the globus pallidus, parts of the amygdala and hippocampus POSTERIOR CIRCULATION Posterior circulation Cerebral hemispheres Brainstem Cerebellum Posterior Cerebral Artery PCA = b l u e ]o A o˙}(Z]vuYY(}}J Cerebellar arteries Vasculature o f cerebellum Arterial supply Globose nuclei rastigia nuclei Superior cerebellar artery Emboliform nuclei Dentate nuclei Anterior inferior cerebellar artery Basilar artery Posterior infe rior cer ebe llar arte ry : Largest branch of the vertebral artery (it can also Vertebral arteries arise from basilar arteries) Posterior inferior cerebellar artery © Provides arterial blood to the cerebellar nuclei and its inferior surface (including the vermis) and the midbrain Summary-lesion localization Lesion Localization can often be inferred based on the neurological deficits and the anatomical structures affected and the crossing of the ascending and descending pathways Motor Lesions: Lesions in the primary motor cortex (precentral gyrus) typically result in contralateral (opposite side of the body) weakness or paralysis. Lesions in the corticospinal tract at different levels can also cause specific motor deficits. For example, a lesion in the brainstem can result in cranial nerve deficits, while lesions in the spinal cord can lead to paralysis or weakness below the level of the lesion. Sensory Lesions: Lesions in the primary sensory cortex (postcentral gyrus) often lead to contralateral sensory deficits, such as loss of touch, temperature sensation, or proprioception. Lesions in the thalamus can disrupt sensory relay and result in sensory deficits on the opposite side of the body. Association Areas: Some sensory and motor functions are more complex and involve association areas in the brain. Lesions in these areas can lead to more nuanced deficits, such as apraxia, neglect, or agnosia.