Presentation on theme: "Chapter 3 CNS Gross Anatomy"— Presentation transcript:
1 Chapter 3 CNS Gross Anatomy Chris RordenUniversity of South CarolinaNorman J. Arnold School of Public HealthDepartment of Communication Sciences and Disorders
2 Key ObjectiveTo be able to identify the level of the CNS by recognizing the landmarks in transverse, horizontal, and coronal sectionsBrain, brainstem, spinal cordRequires practice and drillUse book, atlases and softwareLook for shape, size, location and proximity to other features.
3 Pyramidal Tract Changes Ventricular Changes Easy to spot changesPyramidal Tract ChangesCortical + SubcorticalVentricular ChangesAll levels – including fourth ventricle and brainstemChanges in shape of brainstem and spinal cord
4 Horizontal and Coronal Views Crucial anatomyHorizontal and Coronal ViewsPyramidal TractsCerebellumThalamusInternal CapsuleBasal GangliaPutamenGlobus PallidusCaudate NucleusHippocampusFornixVentriclesCorpus CallosumOptic tractInsula
5 Aka ‘Corticospinal tract’. Pyramidal tractCorona RadiataAka ‘Corticospinal tract’.Massive bundle of axons that contect cortex to spinal cord.Mostly voluntary motor control.
6 M1 is principle origin for pyramidal tract. Primary Motor CortexM1 is principle origin for pyramidal tract.Spatial organization (homunculus)M1: movementS1: sensation
7 Pyramidal CellsNeurons in layers V and VI send axons long distances.Layer V of M1 the pyramidal cells are extremely large. (Betz cells).Dendrites go into superficial layers.Axon travels down pyramidal tract.
8 Corona RadiataNear the motor cortex, we refer to the fibers of the pyramidal tract as being in the ‘corona radiata’.
9 Internal CapsuleNear the basal ganglia, the pyramidal tract forms the central body (genu) of the internal capsule.Internal capsule and neighboring basal ganglia often injured by small strokes.
10 PedunclesPes Pedunculi(part of Cerebral peduncle)APAP
11 Motor Fibers in the Pons ACorticospinal TractAP
16 Look for relationships and shapes of structures Sections of the BrainNote whether views areAxial (Horizontal) ViewsCoronal ViewsLess need for familiarity with sagittal viewLook for relationships and shapes of structures
17 CerebellumHeavily folded appearance – huge number of neurons.
18 ThalamusDifficult to see on MRI scan – similar contrast to nearby white matterMajor portion of diencephalon
19 ThalamusSensory information is relayed to the cortex via the thalamus.Auditory, somatic, visceral, gustatory and vision (but not smell) each have dedicated nuclei in thalamus.Not just relaying information: thalamic nuclei have reciprocal connections with cortex. Regulates level of awareness - damaged can lead to coma.
21 ThalamusNot seen on the more anterior coronal slices.
22 Basal GangliaBasal Ganglia (CN+Putamen referred to as striatum)Caudate nucleus near lateral ventriclePutamen (yellow): superficialGlobus pallidus (green): deepNucleus accumbens: (not shown – junction of CN and Putamen)Function: initiating action. Involved with parkinson disease. Also involved with motivation, addiction.
24 Papez CircuitAHippocampus, fornix and mammillary body crucial for long term memory.A difficult structure to visualize.P
25 HippocampusHippocampus: coronal view reveals folded shape.Fornix also visible in this view.
26 Corpus CallosumMassive white matter bundle that connects the two hemispheres
27 Sometimes surgically severed to treat epilepsy Corpus CallosumSometimes surgically severed to treat epilepsy‘Split brain patients’Connections mostly homotopic
28 The optic tractLesions at different locations lead to different forms of visual field cuts.Important diagnostic tool to infer brain injury.LateralGeniculate Nucleus(Thalamus)V1 Primary Visual Cortex
30 V1Primary visual cortex (V1) lies in calcarine fissure.Complete damage leads to Homonymous hemianopia.Partial damage leads to scotomas
31 V1 – retinotopic mapping V1 is retinotopic: distorted spatial map of visual sceneFovea has massively over represented.
32 Insular CortexInsula: below the portions of the frontal, temporal, and parietal lobesInsula: damage to this area has been linked to verbal dyspraxiaDyspraxia: a dysfunction of motor planning in the absence of muscular weakness or muscular dysfunctionIn the insula, it would be damage producing the simplest verbal gesturesParahippocampus: emotional memory center
33 Insular Cortex Sometimes referred to as Insular Lobe Operculum (lids) separate the insula and the superficial cortex.Temporal Operculum (inferior bank)Parietal Operculum (posterior+superior)Frontal Operculum (anterior+superior)