Central Nervous System (CNS) Part II PDF

CENTRAL NERVOUS SYSTEM (BRAIN AND SPINAL CORD) Jammaella vernice t. gomez, ptrp PART II Central Nervous System During embryonic development, the CNS first appears as a simple tube (neural tube) which extends from the dorsal median plane of the developing embryo’s body. By the 4t...

CENTRAL NERVOUS SYSTEM (BRAIN AND SPINAL CORD) Jammaella vernice t. gomez, ptrp PART II Central Nervous System During embryonic development, the CNS first appears as a simple tube (neural tube) which extends from the dorsal median plane of the developing embryo’s body. By the 4th week, the anterior end of the neural tube begins to expand, and brain formation begins. The rest of the neural tube posterior to the forming brain becomes the spinal cord The central canal of the neural tube which is continuous between the brain and the spinal cord, becomes enlarged into four regions of the brain to form chambers called VENTRICLES Functional Anatomy of the Brain Center of intellect, emotions, Gray matter behavior and memory 4 major regions: cerebral cortex  Cerebral hemispheres  Are actually the cell  Diencephalon bodies of the neurons  Brainstem arranged in a laminar or layered manner  Cerebellum White matter deep into the cerebral cortex  Are actually nerve fibers  White color is d/t myelin Cerebral Hemispheres Paired CH is called cerebrum CORPUS CALLOSUM and is the most superior part A large fiber tract that connects the of the brain and together cerebral hemispheres form:  Arches above the structures of the brain stem and allows the cerebral a. GYRI: elevated ridges of hemispheres to communicate with tissue one another. b. SULCUS: shallow grooves that separates gyri c. FISSURES:deeper grooves that separate large regions of the brain Lobes of the Cerebrum Frontal Lobe behavior and emotion; intelligence; voluntary motion Parietal Lobe tactile and proprioceptive sensation Temporal Lobe  Speech and language; hearing and gustatory Lobes of the Cerebrum Occipital Lobe vision Basal Ganglia helps regulate body tone and for specific body movements Limbic Lobe ”emotional brain” portion of the forebrain concerned with various aspects of emotion and behavior The Brain BrodmanN’s Areas Specialized areas of the cerebrum each with a specific function (represented by numbers) Functional areas which serve a specific sensory, motor and association role on how the cerebrum processes and interprets stimuli BrodmanN’s Areas Brodman’s Areas Sensory Areas Association Areas a. Primary somatosensory areas a. Somatosensory association (areas (areas 3, 1, 2) 5 & 7) b. Primary visual area(area 17) b. Visual association(18 & 19) c. Primary gustatory area(area 43) d. Primary olfactory area c. Auditory association(area 42) Motor Area d. Wernicke’s area(Area 22) a.Primary Motor Area(Area 4) e. Gnstic Area(Area 39) b.Broca’s speech area (Area 44) f. Premotor area(area 6) g. Frontal eye field (area 8) Homunculus Graphic representation of the functional areas of the cerebrum which corresponds to a specific part/organ “visual mapping” 2 types: a. Sensory homunculus b. Motor homunculus Sensory and Motor Homunculus Lateralization of the Cerebrum RIGHT hemisphere LEFT hemisphere spoken and written language musical and artistic numerical and scientific skills awareness ability to use and understand sign space and pattern language perception reasoning recognition of faces and emotional content of facial expressions emotional content of language generating mental images Diencephalon Aka INTERBRAIN Sits atop of the brainstem and is enclosed by cerebral hemispheres MAJOR STRUCTURES: thalamus, hypothalamus, epithalamus and subthalamus Diencephalon Thalamus  Encloses the third ventricle of the brain  Relay station for sensory impulses passing upward to the sensory cortex(touch, pressure,pain and temperature)  Recognition of whether the sensation we are about to perceive is absent or not. Hypothalamus makes up the floor of the diencephalons Important ANS center because it plays a role in the regulation of the body temperature, water balance and metabolism Center of many drives and emotions & behavioral patterns Regulates the pituitary gland Also regulates waking state and patterns of sleep Diencephalon Epithalamus forms the roof of the third ventricle Parts:pineal body and choroids plexus of the third ventricle secretes MELATONIN Subthalamus a small area immediately inferior to the thalamus includes tracts and subthalamic nuclei which connects to the motor areas of the cerebrum helps control body movements BRAINSTEM Part of the brain between the spinal cord and the diencephalons 3 major parts: a.Medulla oblongata b.Pons c.Midbrain Medulla Oblongata Begins at the foramen magnum and extends to the inferior borders of the pons Contains vital reflex centers: a.Cardiovascular center b.Medullary rhythmicity area of respiratory center Have other non-vital centers that controls vomiting, coughing and sneezing Midbrain A.k.a. Mesencephalon Has four rounded elevations (Corpora Quadrigemina) 2 superior elevations: superior colliculi serve as reflex centers that govern movements of the eyes, head and neck in response to visual stimuli 2 inferior elevations: Inferior colliculi reflex centers for the head and trunk in response to auditory stimuli Pons Relays impulses from one side to another and between medulla and midbrain. PNEUMOTAXIC AREA and APNEUSTIC AREA helps control breathing(together with the medulla oblongata) Cerebellum Projects dorsally under the occipital lobe of the cerebrum Provide precise timing for the skeletal muscle activity and controls balance and equilibrium Because of its activity, body movements are smooth and coordinated May have a role in cognition and language processing 3 Major Parts: a. Archicerebellum b. Paleocerebellum c. Neocerebellum SPINAL CORD Anatomy of the Spinal Cord  Starts from foramen magnum to L1 or L2 Entirely enclosed with Spinal or Vertebral Bones External Anatomy of the Spinal Cord  Dura Mater Outermost  Arachnoid Mater  Pia Mater Innermost MENINGEAL COVERINGS OF THE SPINAL CORD  Named based on the corresponding region of the Vertebral Column − Cervical − Thoracic − Lumbar − Sacral − Coccygeal SEGMENTAL DIVISIONS OF THE SPINAL CORD  Each spinal segment will have corresponding nerves emerging from it: SPINAL NERVES − 31 pairs − Conveys somatic sensory/motor & autonomic functions − Later will form the plexuses SPINAL CORD SEGMENTS AND SPINAL NERVES  Eachspinal nerve will exit via INTERVERTEBRAL FORAMEN C6 T10 C6 T11 SKULL C7 T11 C1 C7 T12 C1 C8 T12 C2 T1 L1 C2 T1 L1 C3 T2 L2 T2 SPINAL CORD SEGMENTS AND SPINAL NERVES  At the End of the Spinal Cord: - Conus Medullaris - Cauda Equina  Anchors of the Spinal Cord - Filum Terminale - Denticulate Ligament Other external structures of the spinal cord  Internal aggregation of cell bodies in a distinct “Butterfly Shape” - Gray Matter Periphery comprised of axons - White Matter “Law of Bell & Magendie” INTERNAL ANATOMY OF THE SPINAL CORD CRANIAL NERVES Cranial Nerves  12pairs that leave the brain and pass through foramina and fissures in the skull  Sensory, Motor or Mixed  12 Cranial Nerves I: Olfactory VII: Facial II: Optic VIII: Vestibulocochlear III: Oculomotor IX: Glossopharyngeal IV. Trochlear X: Vagus V: Trigeminal XI: Accessory VI: Abducens XII: Hypoglossal Pure Sensory Cranial Nerves: I: Olfactory II: Optic VIII: Vestibulo-cochlear I: Olfactory Nerve “Most commonly contused CN” Testing of Function (smell) Testing for Rhinorrhea Conditions: Bilateral vs Unilateral Anosmia II: Optic Nerve Testing of Optic Nerve: (Vision) Visual Acuity and Visual Fields. Lesions of the Visual Pathway VIII: Vestibulocochlear Vestibular Aspect Utricle, Saccule and Semicircular Canal For Balance S/Sx: Dizziness, Vertigo and Nystagmus Special test: Dix Hallpike Test Caloric Tests  Auditory Aspect For Hearing S/Sx: Tinnitus, deafness Testing of Hearing: 1. Whisper Test 2. Watch Ticking Test 3. Tuning Fork Test: Weber, Rinne, Bing and Schwabach Meniere’s Disease: Lesion of the internal ear. Fullness of ear and tinnitus. Pure Motor Nerves III: Oculomotor Nerve IV: Trochlear VI: Abducens XI: Accessory XII: Hypoglossal III: Oculomotor Nerve EOM + levator palpebrae superioris + IOM/ smooth muscle for pupillo-constriction (sphincter puppilae and ciliary muscle) Testing of Oculomotor Nerve: Extraocular muscles of the Eyes (c CN IV and VI) Other Areas tested: Direct Light Reflex Consensual Light Reflex Accomodation Reflex Corneal Reflex Visual Body Reflex Pupillary Skin Reflex Impairment of Cranial Nerve III: Complete lesion of CN III Internal Opthalmoplegia vs External Opthalmoplegia IV: Trochlear Nerve Longest and most slender intracranial CN Superior Oblique Condition in the impairment of the trochlear nerve VI: Abducens Nerve Short Lateral Rectus Conditions: Internal Strabismus Internuclear Opthalmoplegia IX: Accessory Nerve Formed by the union of a cranial and spinal (C2, C3, C4) nerve root SCM and upper trapezius XII: Hypoglossal Nerve All the intrinsic muscles of the tongue, palatoglossus, hyoglossus, genioglossus and styloglossus. Impairment of the Hypoglossal nerve Mixed Cranial Nerves (1975) V: Trigeminal VII: Facial IX: Glossopharyngeal X: Vagus V: Trigeminal Branches Ophthalmic Maxillary Mandibular Testing of Trigeminal Nerve: Sensory and Motor Condition: Tic douloureux / trigeminal neuralgia: Unbearable severe pain lasting for seconds over the distribution of CN 5 VII: Facial Nerve Commonly affected in GBS Branches: Temporal Zygomatic Upper buccal Lower Buccal Marginal Mandibular Testing of Facial Nerve Condition of the Facial Nerve: Facial Nerve Lesions 1. Lesion at Pons 2. Lesion at Internal Acoustic Meatus 3. Proximal to the chorda tympani branch in facial canal 4. Firm swelling at the parotid gland 5. ? Hemiplegia vs CN VII injury 6. Bell’s Palsy Special tests for Bell’s Palsy: Bell’s Phenomenon Chvostek Sign Marin Amat Marcus Gunn Comparison of CN V and VII TRIGEMINAL FACIAL Motor Sensory Autonomic Ossicular Muscle Reflexes Comparison of CN V and VII TRIGEMINAL FACIAL Motor Mastication Expression Sensory Autonomic Ossicular Muscle Reflexes Comparison of CN V and VII TRIGEMINAL FACIAL Motor Mastication Expression Sensory Opthalmic, Maxillary, Ant 2/3 of tongue, Mandibular Autonomic Ossicular Muscle Reflexes Comparison of CN V and VII TRIGEMINAL FACIAL Motor Mastication Expression Sensory Opthalmic, Maxillary, Ant 2/3 of tongue, Mandibular Autonomic (-) Lacrimal, salivary Ossicular Muscle Reflexes Comparison of CN V and VII TRIGEMINAL FACIAL Motor Mastication Expression Sensory Opthalmic, Maxillary, Ant 2/3 of tongue, Mandibular Autonomic (-) Lacrimal, salivary Ossicular Tensor Tympani Stapedius Muscle Reflexes Comparison of CN V and VII TRIGEMINAL FACIAL Motor Mastication Expression Sensory Opthalmic, Maxillary, Ant 2/3 of tongue, Mandibular Autonomic (-) Lacrimal, salivary Ossicular Tensor Tympani Stapedius Muscle Reflexes Blink: affector Effector Jaw Reflex IX: Glossopharyngeal Stylopharyngeus and sends secretomotor control to parotid gland Posterior 1/3 of tongue Testing/ Impairment of the Glossopharyngeal Nerve X: Vagus Largest extracranial nerve Testing/ Impairment of the Vagus Nerve Comparison CN IX & X GLOSSOPHARYNGEAL VAGUS Motor Sensory Autonomic Gag reflex Comparison CN IX & X GLOSSOPHARYNGEAL VAGUS Motor Stylopharyngeus Pharyngeal/ Laryngeal Phonation Sensory Autonomic Gag reflex Comparison CN IX & X GLOSSOPHARYNGEAL VAGUS Motor Stylopharyngeus Pharyngeal/ Laryngeal Phonation Sensory Post 1/3 of tongue Pinna of Ear Autonomic Gag reflex Comparison CN IX & X GLOSSOPHARYNGEAL VAGUS Motor Stylopharyngeus Pharyngeal/ Laryngeal Phonation Sensory Post 1/3 of tongue Pinna of Ear Autonomic Parotid gland Heart, Lungs, Liver, Pancreas, Intestine Gag reflex Comparison CN IX & X GLOSSOPHARYNGEAL VAGUS Motor Stylopharyngeus Pharyngeal/ Laryngeal Phonation Sensory Post 1/3 of tongue Pinna of Ear Autonomic Parotid gland Heart, Lungs, Liver, Pancreas, Intestine Gag reflex Afferent, Efferent: Efferent: (Stylopharyngeus) Pharyngeal Constrictor PLEXUSES There are 31 spinal nerves grouped by region of the vertebral column.  Cervical = 8  Thoracic = 12  Lumbar = 5  Sacral = 5  Coccygeal = 1 PLEXUSES Plexuses is a web-like arrangement of nerves that is near the spinal cord and gives rise to terminal nerves.  Cervical plexus – First 5 cervical nerves  Brachial plexus – C5 – T1  Lumbar plexus – L1 – L4  Sacral plexus – L4 – S4 BRACHIAL PLEXUS DERMATOMES and MYOTOMES DERMATOME Root level Cutaneous Area C2 Occipital Protuberance C3 Supraclavicular fossa C4 Top of acromioclavicular joint C5 Lateral antecubital fossa C6 Thumb C7 Middle finger C8 Little finger T1 Medial antecubital fossa T2 Apex of axilla T3 3rd intercostals space (IS) T4 4th IS (nipple level) T5 5th IS T6 6th IS (Xiphisternum) Root level Cutaneous area T7 Continuation of 7th IS to midline T8 Continuation of 8th IS to midline T9 Continuation of 9th IS to midline T10 Continuation of 10th IS to midline T11 Continuation of 11th IS to midline T12 Inguinal ligament in the region of femoral artery L1 1/3 distance of T12 and L2 L2 Mid anterior thigh L3 Medial femoral condyle L4 Medial malleolus L5 Dorsum of foot at big toe S1 Lateral Heel S2 Popliteal Fossa S3 Ischial tuberosity S4-S5 Perianal area MYOTOME Root level Key Muscles C5 Elbow flexors C6 Wrist extensors C7 Elbow extensors C8 Finger flexors T1 Hand intrinsics T1-T12 Chest wall and abdominal muscles L2 Hip flexors L3 Knee extensors L4 Ankle dorsiflexors L5 Toe extensors S1 Ankle plantarflexors S3-S5 Bladder, bower, sex organ, anal and pelvic muscles Thank You!