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Neuroanatomy Diana Stamatopoulos and Raphaëlla Hartman (Credit to: Sara Raza & Mahnoor Shah)AIMS OF THIS TUTORIAL ► Summary of basic neuroanatomy ► Brain basics ► Meninges ► Vasculature ► CSF ► Cranial Nerves ► Summary of functional neuroanatomy ► Main sensory pathways ► Dermatomes ► Main motor pathways ► UMN vs LMN lesionsBrain Hemispheres ► Brain is split into 2 hemispheres by the GREAT LONGITUDINAL FISSURE ► Right hemisphere controls LHS of the body ► Left hemisphere controls RHS of the bodyLobes of the brain Primary motor ctx Primary somatosensory ► Frontal lobe ► Cognition and control and activity movement ► Parietal lobe ► Processes information regarding temp, taste, touch and movement ► Temporal lobe ► Processes memories, integrating them with sensations of taste, sound, sight and touch. ► Occipital lobe ► VisionOther important areas In a right-handed person: ► Broca’s area: left inferior frontal gyrus ► Wernicke’s area: left posterior superior temporal gyrus Temporal lobe (sens) ↓ comprehension Frontal lobe = motor ↓ Speech productionGrey and white matter of brain ► Grey matter: neuronal cell bodies/ ‘soma’ ► White matter: myelinated axons * Corpus callosum *Cerebellum basicsVasculature ACA PCA AICA PICAVasculature continued ► Blue = anterior cerebral artery ► Red = Middle cerebral artery ► yellow = posterior cerebral artery ► Sp.c. supplied by anterior and posterior spinal arteriesHomunculusMCQ Where is Wernicke’s area located? ► A. Right inferior frontal gyrus ► B. Left inferior frontal gyrus ► C. Right posterior superior temporal gyrus ► D. Left posterior superior temporal gyrus ► E. Corpus callosumCSFFlow of CSFMeninges of the Brain ► Dura mater ► Dense irregular connective tissue ► surrounds and supports the dural sinuses (also called dural venous sinuses, cerebral sinuses, or cranial sinuses) and carries blood from the brain toward the heart. ► Arachnoid mater ► Contains the CSF ► Pia mater ► Very thin layer, directly attached to brain parenchymaCranial Nerves ► Many interesting ways to remember the names ► …& modalities Some say marry money, but my brother says big brains matter mostCranial nerve foraminaSo4 LR6 “Lat. rectus”MCQ Which of the following associations is correct? ► A. Trigeminal nerve (CNV): muscles of facial expression ► B. Facial nerve (CNVII): sensation of the face ► C. Glossopharyngeal nerve (CNIX): sensation to anterior ⅓ of the tongue ► D. Abducens nerve (CNIV): superior oblique muscle (eye movement)Part 2: Functional Anatomy► Summary of basic neuroanatomy ► Brain basics ► Meninges ► Vasculature ► CSF ► Cranial Nerves ► Summary of functional neuroanatomy ► Main motor pathways (2) ► Main sensory pathways (3) ► Dermatomes ► UMN vs LMN lesionsPathways to cover ► Motor ► Sensory ► Cortico-bulbar ► Dorsal column ► Cortico-spinal ► Spino-thalamic ► Spino-cerebellar Motor pathway: Corticospinal tract Lateral corticospinal anterior corticospinal Decussate Decussate at junction bt medulla at spinal nerve level and spinal cord (most fibers) (few fibers) …control distal muscles …control axial musclesMotor pathway: Corticobulbar tract ► Supply head and neck ► Relate to the 12 cranial nerves eg. CN12 (tongue) contralateral weaknessKey sensory pathways ► Dorsal column ► Spinothalamic ► Spinocerebellar ► Clinical significanceDorsal column pathway ► fine touch (tactile sensation), vibration and proprioception Gracile nucleus = medial = lower limbs Cuneate nucleus = lateral = upper limbsSpinothalamic Pathway • Anterior spinothalamic tract – carries the sensory modalities of crude touch and pressure. • Lateral spinothalamic tract – carries the sensory modalities of pain and temperature. When in pain, you are quick to be “cross” → decussates in spinal cordSpinocerebellar pathway • Posterior spinocerebellar tract – Carries proprioceptive information from the lower limbs to the ipsilateral cerebellum. • Cuneocerebellar tract – Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum. • Anterior spinocerebellar tract – Carries proprioceptive information from the lower limbs. The fibres decussate twice – and so terminate in the ipsilateral cerebellum. • Rostral spinocerebellar tract – Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.UMN VS LMN Lesions Upper Motor Neurone signs Lower Motor Neurone signs Weakness of voluntary movement of Weakness or paralysis of affected affected muscle muscle No profound muscle atrophy, but slow Profound muscle atrophy wasting over months Spasticity (increased muscle tone due to Tendon reflexes weak or absent continuous stretch reflex) Positive Babinski reflex – dorsiflexion of Fasciculations (irregular muscle big toe when stroking lateral side of sole twitching) of footClinical Significance : Brown Sequard Syndrome● Loss of movement, pain and temperature below level of the lesion ● Position, vibration and touch are in-tact ● Greater motor impairment in upper body > lower body ● Presentation varies depending on size of lesion ● Loss of pain and temperature below level of the lesion ● UMN signs ● Sphincter dysfunction (incontinence) ● Anterolateral pathways and sometimes lateral corticospinal tract involvement ● Contralateral: Loss of pain, temperature and light touch ● Ipsilateral: Loss of vibration, motor function, deep touch and position ● Lateral corticospinal and spinothalamic tracts affectedDermatomesMCQ Which spinocerebellar tract decussates twice? ► A. Posterior ► B. Anterior ► C. Cuneocerebellar ► D. RostralMCQ What spinal cord level provides sensory innervation to the umbilicus? ► A. T10 ► B. T8 ► C. T12 ► D. L1MCQ In Brown-Sequard syndrome: ► A. fine touch is lost on the side of the lesion ► B. pain is lost on the ipsilateral side, below the lesion ► C. pain is lost on the contralateral side, at the level of the lesion ► D. paralysis occurs on the contralateral sideResources ► Teach me anatomy ► Crossman and Neary textbook- illustrated ► https://www.amboss.com/us/knowledge/Cranial_nerve_palsies (everything you need to know about cranial nerves) ► Disclaimer: none of these pictures belong to the presenters, were all taken off of google imagesFeedback ►Please take a minute now before you leave to fill in a quick feedback form: ► https://app.medall.org/feedback/feedback-flow?keyword=a9199f00519df4c0a3 d4b0c2&organisation=accessibility-in-medicineAIM F ACEBOOK P AGE • Give our Facebook page a like for updates and opportunities, just search @AIMEdinburgh ► If you have any more questions, feel free to email accessibilityinmedicine@gmail.com