The Brain and Cranial Nerves
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Cranial Nerve Palsy
Cranial Nerve Palsy What is a cranial nerve? Cranial nerves are nerves that lead directly from the brain to parts of our head, face, and trunk. There are 12 pairs of cranial nerves and some are involved in special senses (sight, smell, hearing, taste, feeling) while others control muscles and glands. Which cranial nerves pertain to the eyes? The second cranial nerve is called the optic nerve. It sends visual information from the eye to the brain. The third cranial nerve is called the oculomotor nerve. It is involved with eye movement, eyelid movement, and the function of the pupil and lens inside the eye. The fourth cranial nerve is called the trochlear nerve and the sixth cranial nerve is called the abducens nerve. They each innervate an eye muscle involved in eye movement. The fifth cranial nerve is called the trigeminal nerve. It provides facial touch sensation (including sensation on the eye). What is a cranial nerve palsy? A palsy is a lack of function of a nerve. A cranial nerve palsy may cause a complete or partial weakness or paralysis of the areas served by the affected nerve. In the case of a cranial nerve that has multiple functions (such as the oculomotor nerve), it is possible for a palsy to affect all of the various functions or only some of the functions of that nerve. What are some causes of a cranial nerve palsy? A cranial nerve palsy can occur due to a variety of causes. It can be congenital (present at birth), traumatic, or due to blood vessel disease (hypertension, diabetes, strokes, aneurysms, etc). -
Cranial Nerve VIII
Cranial Nerve VIII Color Code Important (The Vestibulo-Cochlear Nerve) Doctors Notes Notes/Extra explanation Please view our Editing File before studying this lecture to check for any changes. Objectives At the end of the lecture, the students should be able to: ✓ List the nuclei related to vestibular and cochlear nerves in the brain stem. ✓ Describe the type and site of each nucleus. ✓ Describe the vestibular pathways and its main connections. ✓ Describe the auditory pathway and its main connections. Due to the difference of arrangement of the lecture between the girls and boys slides we will stick to the girls slides then summarize the pathway according to the boys slides. Ponto-medullary Sulcus (cerebello- pontine angle) Recall: both cranial nerves 8 and 7 emerge from the ventral surface of the brainstem at the ponto- medullary sulcus (cerebello-pontine angle) Brain – Ventral Surface Vestibulo-Cochlear (VIII) 8th Cranial Nerve o Type: Special sensory (SSA) o Conveys impulses from inner ear to nervous system. o Components: • Vestibular part: conveys impulses associated with body posture ,balance and coordination of head & eye movements. • Cochlear part: conveys impulses associated with hearing. o Vestibular & cochlear parts leave the ventral surface* of brain stem through the pontomedullary sulcus ‘at cerebellopontine angle*’ (lateral to facial nerve), run laterally in posterior cranial fossa and enter the internal acoustic meatus along with 7th (facial) nerve. *see the previous slide Auditory Pathway Only on the girls’ slides 04:14 Characteristics: o It is a multisynaptic pathway o There are several locations between medulla and the thalamus where axons may synapse and not all the fibers behave in the same manner. -
Clinical Anatomy of the Cranial Nerves Clinical Anatomy of the Cranial Nerves
Clinical Anatomy of the Cranial Nerves Clinical Anatomy of the Cranial Nerves Paul Rea AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier Academic Press is an imprint of Elsevier 32 Jamestown Road, London NW1 7BY, UK The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK Radarweg 29, PO Box 211, 1000 AE Amsterdam, The Netherlands 225 Wyman Street, Waltham, MA 02451, USA 525 B Street, Suite 1800, San Diego, CA 92101-4495, USA First published 2014 Copyright r 2014 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangement with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. -
The Vestibulocochlear Nerve (VIII)
Diagnostic and Interventional Imaging (2013) 94, 1043—1050 . CONTINUING EDUCATION PROGRAM: FOCUS . The vestibulocochlear nerve (VIII) a,∗ b a F. Benoudiba , F. Toulgoat , J.-L. Sarrazin a Department of neuroradiology, Kremlin-Bicêtre university hospital, 78, rue du Général-Leclerc, 94275 Le Kremlin-Bicêtre, France b Diagnostic and interventional neuroradiology, Laennec hospital, Nantes university hospitals, boulevard Jacques-Monod, Saint-Herblain, 44093 Nantes cedex 1, France KEYWORDS Abstract The vestibulocochlear nerve (8th cranial nerve) is a sensory nerve. It is made up of Cranial nerves; two nerves, the cochlear, which transmits sound and the vestibular which controls balance. It is Pathology; an intracranial nerve which runs from the sensory receptors in the internal ear to the brain stem Vestibulocochlear nuclei and finally to the auditory areas: the post-central gyrus and superior temporal auditory nerve (VIII) cortex. The most common lesions responsible for damage to VIII are vestibular Schwannomas. This report reviews the anatomy and various investigations of the nerve. © 2013 Published by Elsevier Masson SAS on behalf of the Éditions françaises de radiologie. The cochlear nerve Review of anatomy [1] The cochlear nerve has a peripheral sensory origin and follows a centripetal path. It ori- ginates in the cochlear membrane sensory canal, forming the spiral organ (the organ of Corti) and lies on the basilar membrane (Fig. 1). The neuronal fibers of the protoneu- ron connect to the ciliated cells on the spiral lamina (Fig. 2). The axons are grouped together along the axis of the cochlea (modiolus), forming the cochlear nerve which then enters the internal auditory meatus (IAM). Within the internal auditory meatus, the nerve joins the vestibular nerve to form the vestibulocochlear nerve which crosses the cere- bellopontine angle (Figs. -
Lecture 6: Cranial Nerves
Lecture 6: Cranial Nerves Objective: To understand the organization of cranial nerves with respect to their nuclei within the brain, their course through and exit from the brain, and their functional roles. Olfactory Eye Muscles 3, 4 &6 Cranial Nerves 1-7 I overview Table, Page 49 II Lecture notes Cranial Nerves and their Functions V Trigeminal VII Facial VIII IX X XII XI Cranial Nerves 8-12 Overview sternocephalic I. Factors Responsible for the Complex Internal Organization of the Brain Stem-> leads to altered location of cranial nerve nuclei in adult brain stem 1. Development of the Fourth Ventricle a. Medulla and Pons develop ventral to the 4th ventricle cerebellum b. Alar plate is displaced lateral to basal plate 4 Medulla Developing Neural Tube 2. Cranial nerve nuclei form discontinuous columns Rostral 12 SE Page 48 Notes 3. Some cranial nerve nuclei migrate from their primitive embryonic positions (e.g., nuclei of V and VII) Facial N. Factors responsible for the complex internal organization of the brainstem: 4) Special senses develop in association with the brain stem. Nuclei of special senses 5) Development of the cerebellum and its connections Cerebellum II. Cranial Nerve Nuclei: Nucleus = column of neuron cell bodies. Efferent nuclei are composed of cell bodies of alpha or gamma motor neurons (SE) or preganglionic parasympathetic neurons (VE). III. Motor Efferent Nuclei (Basal Plate Derivatives): 1. SE (Somatic Efferent) Nuclei: SE neurons form two longitudinally oriented but discontinuous columns of cell bodies in the brain stem. Neurons that comprise these columns are responsible for innervating all of the skeletal musculature of the head. -
Cranial Nerves
Cranial Nerves Cranial nerve evaluation is an important part of a neurologic exam. There are some differences in the assessment of cranial nerves with different species, but the general principles are the same. You should know the names and basic functions of the 12 pairs of cranial nerves. This PowerPage reviews the cranial nerves and basic brain anatomy which may be seen on the VTNE. The 12 Cranial Nerves: CN I – Olfactory Nerve • Mediates the sense of smell, observed when the pet sniffs around its environment CN II – Optic Nerve Carries visual signals from retina to occipital lobe of brain, observed as the pet tracks an object with its eyes. It also causes pupil constriction. The Menace response is the waving of the hand at the dog’s eye to see if it blinks (this nerve provides the vision; the blink is due to cranial nerve VII) CN III – Oculomotor Nerve • Provides motor to most of the extraocular muscles (dorsal, ventral, and medial rectus) and for pupil constriction o Observing pupillary constriction in PLR CN IV – Trochlear Nerve • Provides motor function to the dorsal oblique extraocular muscle and rolls globe medially © 2018 VetTechPrep.com • All rights reserved. 1 Cranial Nerves CN V – Trigeminal Nerve – Maxillary, Mandibular, and Ophthalmic Branches • Provides motor to muscles of mastication (chewing muscles) and sensory to eyelids, cornea, tongue, nasal mucosa and mouth. CN VI- Abducens Nerve • Provides motor function to the lateral rectus extraocular muscle and retractor bulbi • Examined by touching the globe and observing for retraction (also tests V for sensory) Responsible for physiologic nystagmus when turning head (also involves III, IV, and VIII) CN VII – Facial Nerve • Provides motor to muscles of facial expression (eyelids, ears, lips) and sensory to medial pinna (ear flap). -
The Brain and Cranial Nerves Glioblastoma (Red), a Fast-Growing, Highly Invasive Brain Tumor (MRI) CHAPTER OUTLINE
Saladin: Anatomy & 14. The Brain and Cranial Text © The McGraw−Hill Physiology: The Unity of Nerves Companies, 2003 Form and Function, Third Edition CHAPTER 14 The Brain and Cranial Nerves Glioblastoma (red), a fast-growing, highly invasive brain tumor (MRI) CHAPTER OUTLINE Overview of the Brain 516 The Forebrain 529 • Directional Terms in Neuroanatomy 516 • The Diencephalon 530 INSIGHTS • Major Landmarks of the Brain 516 • The Cerebrum 531 • Gray and White Matter 516 14.1 Clinical Application: • Embryonic Development 517 Higher Brain Functions 536 Meningitis 521 • Brain Waves and Sleep 536 14.2 Medical History: The Accidental Meninges, Ventricles, Cerebrospinal Fluid, • Cognition 538 Lobotomy of Phineas Gage 538 and Blood Supply 519 • Memory 539 14.3 Clinical Application: Some Cranial • Meninges 519 • Emotion 539 Nerve Disorders 556 • Ventricles and Cerebrospinal Fluid 521 • Sensation 540 14.4 Clinical Application: Images of the • Blood Supply and the Brain Barrier • Motor Control 542 Mind 557 System 524 • Language 543 • Cerebral Lateralization 543 The Hindbrain and Midbrain 524 • The Medulla Oblongata 524 The Cranial Nerves 546 • The Pons and Cerebellum 526 • The Cranial Nerves—An Aid to Memory 547 • The Midbrain 526 • The Reticular Formation 528 Chapter Review 558 Brushing Up To understand this chapter, it is important that you understand or brush up on the following concepts: • Anatomy of the cranium (pp. 248–257) • Glial cells and their functions (pp. 450–451) • Tracts of the spinal cord (pp. 486–489) • Structure of nerves and ganglia (pp. 490–492) 515 Saladin: Anatomy & 14. The Brain and Cranial Text © The McGraw−Hill Physiology: The Unity of Nerves Companies, 2003 Form and Function, Third Edition 516 Part Three Integration and Control he mystique of the brain continues to intrigue modern biologists of its major landmarks (figs. -
Cranial Nerves: Anatomy and Physiology
APPENDIX Cranial Nerves: Anatomy and Physiology We have 12 cranial nerves; some are sensory nerves, some are motor nerves, and some are part of the autonomic nervous system. I. Olfactory Sensory: Smell II. Optic Sensory: Vision III. Oculomotor Motor: Eye Movements: Innervates all extraocular muscles, except the superior oblique and lateral rectus mus- cles. Innervates the striated muscle of the eyelid. Autonomic: Mediates pupillary constriction and accommodation for near vision. IV. Trochlear Motor: Eye Movements: Innervates superior oblique muscle. V. Trigeminal Sensory: Mediates cutaneous and proprioceptive sensations from skin, muscles, and joints in the face and mouth, includ- ing the teeth and the anterior two-thirds of the tongue. Motor: Innervates muscles of mastication. VI. Abducens Motor: Eye Movements: Innervates lateral rectus muscle. VII. Facial Motor: Innervates muscles of facial expression. Autonomic: Lacrimal and salivary glands. Sensory: Mediates taste and possible sensation from part of the face (behind the ear). Nervous intermedius: Pain around the ear; possibly taste. VIII. Vestibulocochlear Sensory: Hearing Equilibrium, postural reflexes, orientation of the head in space. IX. Glossopharyngeal Sensory: Taste Innervates taste buds in the posterior third of tongue. Sensory: Mediates visceral sensation from palate and posterior third of the tongue. Innervates the carotid body. Motor: Muscles in posterior throat (stylopharyngeal muscle). Autonomic: Parotid gland. X. Vagus Sensory: Mediates visceral sensation from the pharynx, larynx, thorax, and abdomen. Innervates the skin in the ear canal and taste buds in the epiglottis. Autonomic: Contains autonomic fibers that innervate smooth mus- cle in heart, blood vessels, trachea, bronchi, esopha- gus, stomach, and intestine. Motor: Innervates striated muscles in the soft palate, pharynx, and the larynx. -
Brainstem Reflexes Herniation Syndromes (CN IX-XII) Lab 7 March 24, 2021 - Dr
Brainstem Reflexes Herniation Syndromes (CN IX-XII) Lab 7 March 24, 2021 - Dr. Krebs ([email protected]) Objectives: 1. Describe the relationship of the functional anatomy of CN IX - XII and the location of their respective nuclei to a neurological exam which examines the brainstem. 2. Explain the neuroanatomical pathways associated with brainstem reflexes tested in the conscious and unconscious patient. 3. Describe the relationship between the sympathetic and parasympathetic innervation of the eye to the clinical assessment of eye reflexes. 4. Describe the relationship of changes in upper limb posture of unconscious patient to underlying damage to the brainstem. 5. Describe the consequences of herniation syndromes associated with increases in intracranial pressure. Videos for Review: Notes: • For identification of the cranial nerves, use online modules and videos, your atlas and micrographs to locate the nuclei listed. • On the brain and brainstem specimens, locate cranial nerves IX, X, XI and XII. Note the level at which they are attached to the brainstem. ** NOTE: Interactive PDFs are best viewed on desktop/laptop computers - functionality is not reliable on mobile devices ** Design & Artwork: The HIVE (hive.med.ubc.ca) 1 Brainstem Reflexes Herniation Syndromes (CN IX-XII) Lab 7 March 24, 2021 - Dr. Krebs ([email protected]) Glossopharyngeal Nerve (CN IX) Modality Associated Nucleus Function Motor Nucleus ambiguus Motor to stylopharyngeus muscle (SVE) Parasympathetic Inferior salivatory nucleus Stimulation of parotid gland (GVE) Taste Solitary nucleus and tract Taste from posterior 1/3 of tongue (SVA) Somatic Sensory Spinal trigeminal nucleus and General sensation from posterior 1/3 of tongue, (GSA) tract pharynx, external ear/tympanic membrane Visceral Sensory Solitary nucleus and tract Carotid body, gag sensation from oropharynx (GVA) Which foramen does CN IX exit through? Highlight and label the nuclei associated with CN IX in this diagram and show the types of fibres that comprise this peripheral nerve. -
Cranial Nerves. Sensory Organs
Kharkiv National Medical University, Department of Human Anatomy CRANIAL NERVES. SENSORY ORGANS. The cranial nerves are: CN I - Olfactory Nerve CN II - Optic Nerve CN III - Oculomotor Nerve CN IV - Trochlear Nerve CN V - Trigeminal Nerve CN VI - Abducens Nerve CN VII - Facial Nerve CN VIII - Vestibulocochlear Nerve CN IX - Glossopharyngeal Nerve CN X - Vagus Nerve CN XI - Accessory Nerve CN XII - Hypoglossal Nerve Classification of the Cranial Nerves It is possible to describe a cranial nerve in terms of its function and embryological origin, initially cranial nerves can be subdivided into being either: Motor (efferent) Sensory (afferent) And from there further categorization can occur. Motor (efferent) Cranial nerves -Somatic motor (general somatic efferent) (III, IV, VI, XII) These cranial nerves are so called because they innervate muscles derived from the occipital somites, such as the extra ocular and extrinsic tongue muscles. Sensory (afferent) cranial nerves -Visceral sensory special visceral afferent- (VII, IX, X) general visceral afferent- (IX, X) The name is related to the fact that it detects sensation from visceral organs. They are divided into special visceral, referring to the rostral portion of the nucleus which contributes to the special sensation of taste. Whilst the general visceral portion is named as such due to this caudal portion receiving general sensory impulses such as cardiac, respiratory . - General somatic sensory (general somatic afferent) (V, VII, IX, X) These nuclei detect general sensation, such as touch, pain, vibration from the face, sinuses and meninges - Special somatic sensory (special somatic) (VIII) This carries information from the special sensation of hearing and balance. -
Introductory Chapter: Facial Nerve - an Overview Isam Jaber Al-Zwaini and Mohammed Jalal Hussein
Chapter Introductory Chapter: Facial Nerve - An Overview Isam Jaber Al-Zwaini and Mohammed Jalal Hussein 1. Introduction The facial nerve (seventh cranial nerve—CNVII) is the nerve of facial expres- sion. It innervates all superficial muscles of the face and scalp, the contraction of which is responsible for all our numerous facial expressions like anger, pain, fear, smile, etc. Facial disfigurement resulting from facial nerve disorders can affect the physical, psychological, and emotional integrity of an individual. This might result in social, occupational, and educational handicap. The facial nerve is one of the most common cranial nerves implicated by disorders. It is a mixed nerve, which carries motor, sensory, and parasympathetic fibers. The motor fiber-innervated muscles developed from second branchial arch, the sensory fibers transmit the special sense of taste, and the parasympathetic fibers supply the submandibular, sublingual, and lacrimal glands [1]. Embryologically speaking, it is formed very early within the acousticofacial complex from the second branchial arch [2]. Facial nerve consists of the juxtaposition of somatic and branchial elements of the cranial nerve nuclei, in particular, accounting for trigeminal and facial nerve anastomosis [3]. A wide variety of disorders can involve the facial nerve including congenital, traumatic, infectious, inflammatory, and neoplastic disorders. 2. Anatomy The anatomy of the facial nerve is the most complex among other cranial nerves. It composed of approximately 10,000 neurons. Seven thousands of these fibers are myelinated and innervate the muscles of facial expression and the stapedial muscle. The other 3000 nerve fibers form the nervus intermedius with a secretary and somatosensory component. -
FUNCTIONAL HUMAN ANATOMY LAB #3 Brain, Spinal Cord and Cranial Nerves
Lab 3 FUNCTIONAL HUMAN ANATOMY LAB #3 Brain, Spinal Cord and Cranial Nerves BRAIN: Frontal lobes Temporal lobes Correspond to the flat bones of the skull that cover the parts of the Parietal lobes cerebrum Occipital lobes Cerebellum Pons Medulla Oblongata (typically where the brain is severed during dissection) Corpus Callosum (where the cerebral hemispheres join; can be seen within the longitudinal cerebral fissure) Meninges and spaces: (superficial to deep - can be seen in both the brain and spinal cord) Epidural space (potential space in the cranium; actual space in the vertebral canal) Dura matter (very thick, easily palpable, opaque) Sub-dural space Arachnoid matter (very thin, transparent, easier to probe in the brain) Sub-arachnoid space (contains CSF fluid and much vasculature) Pia matter (non-dissectable) 12 CRANIAL NERVES: (know general innervations/functions) (CN I) Olfactory Sensory only - smell; courses on the inferior side of the frontal lobes and parallel to the cribriform plate; nerves go through the perforations in the plate to access the nasal cavity (CN II) Optic Sensory only - vision; processes light information and turns it into a picture that your brain can recognize (CN III) Oculomotor Motor and sensory function for the eyes; motor to all muscles except superior oblique m. and lateral rectus m.; controls ciliary muscle (lens) and sphincter muscle (iris); sensory - proprioception (CN IV) Trochlear Motor and sensory function for the eyes; motor to superior oblique muscle; sensory - proprioception (CN VI) Abducens