Functional Neuroanatomy: An Interactive Text and Manual / Edition 1

by Jeffrey T. Joseph, David L. Cardozo

Overview

An engaging and highly novel presentation of functional neuroanatomy, Functional Neuroanatomy provides a thorough understanding of the function of the central nervous system. Its takes a problem- and exercise-based approach to the material, with everything from dissections, radiological material, and histology to clinical cases and experimental data. The text shows histology of various neurological disorders, accompanied by descriptions of clinically relevant pathology. Numerous patient presentations support the case studies by offering real examples of how functional neuroanatomy applies to clinical problems.
Taking a highly interactive approach to the field, the text offers over 500 clearly labeled images of gross, microscopic, and radiological images. It cross-references between chapters and reinforces concepts introduced earlier. The emphasis stays on clinical relevance throughout, and the book concludes with an atlas of labeled gross structures and cross-sections.

Product Details

ISBN-13:	9780471444374
Publisher:	Wiley
Publication date:	02/04/2004
Pages:	592
Product dimensions:	8.29(w) x 10.98(h) x 1.08(d)

About the Author

Dr. Joseph is a neuropathologist at the Beth Israel Deaconess Medical Center. He received his medical and doctoral training at Harvard Medical School. He trained in anatomic pathology and then neuropathology at the Brigham and Women’s Hospital and Children’s Hospital in Boston. In addition to providing clinical neuropathology service at the Beth Israel Deaconess, he is also assistant course director of Human Nervous System and Behavior, the main preclinical neuroanatomy and neurophysiology course at Harvard Medical School. Dr. Joseph has taught extensively, including in the Peace Corps and in graduate school, and has taught at Harvard Medical School since 1996. Over the years he has accumulated an extensive collection of neuroanatomy and neuropathology images, some of which are used in this text.

Dr. Cardozo is a faculty member in the Department of Neurobiology at Harvard Medical School and is course director for the Human Nervous System and Behavior at Harvard Medical School. He received a B.A in English Literature from Concordia University, a B.S. in Biology from Dalhousie University and a Ph.D. in Neurobiology from Harvard University. Prior to embarking upon an academic career, he served as an officer in the Canadian Navy and as a master of cargo vessels trading in the Caribbean. He has taught at Harvard Medical School since 1998.

Read an Excerpt

Functional Neuroanatomy

An Interactive Text and Manual

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By Jeffrey T. Joseph David L. Cardozo

John Wiley & Sons

Copyright © 2004 John Wiley & Sons, Inc.
All right reserved.
ISBN: 0-471-44437-5

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Chapter One

EXTERNAL ANATOMY

Our nervous system starts life as a groove on the surface of the embryo and rapidly closes to become a tube. To form the central nervous system, this tube kinks in several spots and proliferates to its final form. Crested offshoots from the tube form the peripheral nervous system. Several layers of protection envelop the developing brain. To support its gelatinous substance, the brain floats in water. Our brain connects to the body via a complex system of nerves and receives sustenance from the body by a complex of vessels.

In this first laboratory session you will focus on three main topics: (1) the overall structure and organization of the brain and spinal cord as revealed by their external anatomy, (2) the brain's critically important vascular supply, and (3) the brain's protective coverings. As you work through this lab, concentrate on obtaining an overview of the general structure of the nervous system and avoid worrying too much about the thousands of details that we will be largely ignoring today. We will revisit all of these structures many times throughout the remaining laboratories and will have lots of opportunity to think about them in greatdepth.

Before beginning these laboratories, it is important to remind you to always wear gloves when handling human nervous tissue. An extremely rare brain disease (we're literally talking one in a million) has been shown to be transmitted by brain tissue. This class of diseases is known by several names, including Prion diseases, spongiform encephalopathies, and Creutzfeldt-Jacob disease (CJD). Popular names for similar animal diseases include "mad cow disease" and scrapie. The "infectious agent" of such afflictions is very hardy, surviving formalin fixation, paraffin embedding, regular autoclaving, and other standard measures. However, transmission has only been documented by direct brain inoculation, or in some cases by ingestion. You probably won't do either. NO EATING IN THE LABORATORY, WEAR GLOVES WHEN HANDLING BRAIN TISSUE, and BE CAUTIOUS WITH THE DISSECTING EQUIPMENT.

LEARNING OBJECTIVES

Know the main divisions of the brain and their functional relationships.

Recognize the salient morphological features on the lateral and medial brain surfaces.

Identify the main vessels that serve the brain, distinguish their territories, and understand the perfusion of the brain.

Identify the main features of the brain's coverings and their relationship to the blood vessels.

Relate the brain specimen to radiological images.

Relate the spinal cord to the vertebral column and its significance in lumbar puncture.

INTRODUCTION

The goal of this first chapter is to introduce you to the overall structure and organization of the brain and spinal cord, including their vascular supply and protective coverings.

Neuroanatomy is a vast and complex subject. In order to approach it successfully, you need to order your approach. The secret to a successful attack on the discipline is to intellectually divide the nervous system into the largest chunks of information first, followed by successively finer and finer grains of information. For instance, your first major "cut" should establish that the central nervous system consists of the brain and the spinal cord. Next, before you learn any details of a particular region, recognize that the brain consists of a forebrain, midbrain, and hindbrain. Follow this with the next logical subdivisions of forebrain into cortex, basal ganglia, and thalamus; and hindbrain into cerebellum, pons, and medulla. If you maintain this simple approach of acquiring your neuroanatomical sophistication in incremental steps, you'll find that it is a pleasant way to learn the material, it will make more sense to you, and the knowledge will remain with you.

As you are studying neuroanatomy, always keep in mind that the entire nervous system develops from a neural tube that bulges, bends, and kinks in various ways and places to give the brain its characteristic structure. By relating any structure in the adult nervous system to its origin in the neural tube, you will able to see the logic of its position. For instance, the three main divisions of the brain: the forebrain, midbrain, and hindbrain, arise from three primary bulges in the neural tube (see Fig. 1.1). Similarly, the ventricles are simply what is left of the hollow portion of the tube after the contortion act is completed. They are narrowed where developing nervous tissue has bulged inward, and they are bent where the neural tube has grown back on itself. The same holds true for gray matter structures. The caudate nucleus, as an example, arises as an inward bulge at the lateral base of the neural tube. Consequently it will always be found at "bottom" of the lateral ventricles.

TERMINOLOGY

A unified neuroanatomical terminology is used throughout the neurosciences. It is based on an ideal vertebrate whose nervous system is linearly organized like that of the dog shown in Figure 1.2.

Structures are oriented as being:

Rostral (toward the nose) or caudal (toward the tail)

Dorsal (toward the back) or ventral (toward the belly)

Anterior (toward the front) or posterior (toward the rear)

Superior (toward the upper side) or inferior (toward the lower side)

Medial (toward the midline) or lateral (toward side)

These terms are applied in slightly different ways to structures in forebrain as opposed to their use in the brainstem and spinal cord. This is because we stood up. The human nervous system bends approximate 90° at the junction between the midbrain and the forebrain (Figure 1.2B). In the spinal cord, dorsal/ventral and anterior/posterior indicate the same relationships. For example, the large tracts of sensory fibers on the dorsal surface of the spinal cord are termed "dorsal columns" as well as "posterior columns." Similarly the site of concentration of motor nerve cells in the spinal cord is known as both the "ventral horn" and the "anterior horn." In the forebrain, anterior/posterior indicates the direction along the axis of the nervous system and is used in the same sense as rostral/caudal in the spinal cord. Dorsal/ventral and medial/lateral have the same meaning in the forebrain as in the spinal cord.

The most frequently used planes of section for the study of brain anatomy are (1) horizontal, (2) coronal, and (3) sagittal (see Fig. 1.3). These terms reflect the approach to dissection. The brain can be cut in parallel horizontal slices from top to bottom, or in anterior-to-posterior transverse sections (coronal), or in medial-to-lateral sections (sagittal). The term coronal is primarily used in reference to the cross-sectional plane of the forebrain, while transverse is used when referring to cross sections of the brainstem and spinal cord. These approaches to brain cutting are so established in tradition that they are also used in the presentation of standard brain imaging studies.

External Anatomy of the Brain and Spinal Cord

The central nervous system is composed of the spinal cord, contained within the vertebral canal, and the brain (encephalon) located within the skull. The brain itself is divided into the cerebral cortex and its basal ganglia, the thalamus and hypothalamus, the transitional midbrain, and the parts of the brain in the posterior fossa (cerebellum, pons, and medulla). These terms are often grouped together, either in clinical usage or in research. Starting from the midbrain, or mesencephalon, the caudal structures are termed the hindbrain, which includes the cerebellum, pons, and medulla. The diencephalon lies immediately rostral to the mesencephalon and contains the thalamus and hypothalamus. Given our anthropocentric views, the cerebral cortex and its basal ganglia are called the "final brain" or telencephalon. The forebrain (or the less common prosencephalon) groups those brain areas rostral to the mesencephalon. Of the terms used in a classification derived from embryology (the "cephalon" words), the ones most commonly used in adult neurology as adjectives to denote a rostro-caudal "level" are diencephalic and mesencephalic (see Fig. 1.4)

The spinal cord is the caudal continuation of the medulla. It is about 46 cm long and extends from the atlas (like the Greek god Atlas holding the world, as this is the bone holding the skull), to approximately L1/L2 where it ends in the conus medullaris. The cord gives off dorsal and ventral nerve roots at each segmental level. The roots pass through an intervertebral foramen and project out to the body. They also send collaterals to the sympathetic chain ganglia that lie outside the vertebral column. The nerve roots exiting below L1/L2 form the cauda equina (horse's tail).

Blood Supply

Specific brain functions are, to a great extent, localized to particular brain areas; these areas, in turn, are perfused by unique arteries. Consequently a malfunction in a given vessel often leads to a specific functional deficit. For example, a small thrombotic occlusion of the posterior cerebral artery can result in unilateral cortical blindness. In this laboratory you will focus on the vascular territories and on the overall path of the circulation.

The main blood supply to the brain comes from two paired sources, the vertebral arteries and the internal carotid arteries. The vertebral arteries ascend on the ventral surface of the medulla and fuse at the level of the pons, where they form the single basilar artery. The left and right internal carotid arteries each run directly into opposite sides of the circle of Willis. Blood supplied by the internal carotid arteries is often referred to as the anterior circulation, and that supplied by the vertebral and basilar arteries as the posterior circulation. The blood supply to the spinal cord is provided by the anterior spinal and the two posterior spinal arteries that are fed by variable radicular arteries. Blood drains from the brain into veins, then into venous sinuses, and leaves the head via the jugular veins and to a much lesser extent, via the vertebral veins. Blood leaves the spinal cord via an intricate venous system.

Brain Coverings

The brain and spinal cord are delicate organs that have a jelly-like consistency. These highly vulnerable structures are protected by the skull and vertebral column, several membrane covers, and by the cerebrospinal fluid (CSF), which provides a cushion against compressive shock. The three membranes covering the brain working from the skull inward, are the dura mater, the arachnoid mater, and the pia mater (see Fig. 1.5). The dura is a rather tough membrane that can only be torn by hand with some difficulty. It consists of two leaves: an outer periosteal layer that adheres to the inner surface of the skull, and an inner layer. The two dural layers cannot be distinguished from one another except where they depart from the conformation of the skull, and dive into the brain forming the interhemispheric falx and the tentorium overlying the cerebellum, or where they split apart to form the venous sinuses. The sinuses serve to collect blood from the veins of the brain. At the superior sagittal sinus, CSF is resorbed into the venous system.

The middle membrane, the arachnoid, has a smooth outer surface and is devoid of vasculature. Like the dura, the arachnoid covers the brain's surface without descending into the individual sulci. Thin, branching filamentous structures extend from its inner surface to the pia mater below giving the arachnoid a weblike appearance. The pia, the thin innermost membrane is closely adherent to the surface of the brain and spinal cord. It follows the brain surface perfectly, covering gyri and sulci alike. Since the arachnoid bridges the sulci and fissures on the surface of the brain and spinal cord, it forms subarachnoid spaces of variable size, containing CSF. The largest spaces are called cisterns.

Because of the continuity of the membranes covering the brain, in certain disease states the region between these membrane may become filled with fluids, blood, air, or tumor. Since these regions are not normally open, they are termed potential spaces. Between the skull (or vertebra) and the dura is a potential space called the epidural (or extradural) space, containing only blood vessels. Under the meningeal layer of dura, between it and the arachnoid, is a potential space called the subdural space. Head trauma can cause bleeding within this space and lead to a subdural hematoma. The gap between the pia and arachnoid is called the subarachnoid space. Since these three spaces have different classes of blood vessels associated with them, characteristic types of "bleeds" result from damage to each class of vessel.

Schedule (2.5 hours)

60 External anatomy 20 Spinal cord 20 Vessels 30 Coverings 20 Case

EXTERNAL BRAIN

General Orientation of the Brain

INST Examine your whole and half brain specimens and spinal cord. Using Figure 1.2 and 1.6, review the following terms by relating them to the specimens:

Anterior versus posterior

Rostral versus caudal

Ventral versus dorsal

Lateral versus medial

Superior versus inferior

INST Using imaginary cuts on your specimens and Figure 1.3, go through the following planes of section:

Horizontal

Sagittal

Parasagittal

Coronal and transverse

Q1.1. Where do you find transverse sections used?

A1.1. Brainstem and spinal cord.

Major Divisions

INST Using anatomic specimens, identify the four major divisions of the brain: the cerebrum, brainstem, cerebellum, and spinal cord.

Q1.2. What structures lie immediately above and below the junction between the brainstem and cerebrum?

A1.2. The midbrain is the caudal part of this junction, while the thalamus or diencephalon lies rostral to the junction.

Q1.3. What separates the cerebellum from the cerebral hemispheres?

A1.3. The transverse fissure and tentorium.

Cerebral Hemispheres

Q1.4. The cerebral cortex is divided into four major lobes (frontal, parietal, temporal, and occipital) and the smaller insula. In order to determine their boundaries, you have to first recognize the major sulci. Use your whole brain to locate the structures below and label them on Figure 1.7. First locate the longitudinal fissure. Next identify the Sylvian fissure. Then identify the central sulcus. It's not always easy to pick out. The easiest way to locate it is on the medial surface of the half brain.

Continues...

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Excerpted from Functional Neuroanatomy by Jeffrey T. Joseph David L. Cardozo Copyright © 2004 by John Wiley & Sons, Inc.. Excerpted by permission.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

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Table of Contents

Preface.

1. External Anatomy.

2. Internal Anatomy.

3. Histology.

4. Neuroimaging.

5. Somatosensory System.

6. Craniosensory Systems.

7. Vision and Hearing.

8. Neuromuscular System (with David Dawson).

9. Basal Ganglia.

10. Cerebellum.

11. Brainstem and Control Systems.

12. Cranial Nerves.

13. Hypothalamus.

14. Limbic System (with Changiz Geula).

15. Cortex (with Changiz Geula).

16. Development.

17. Trauma.

18. Review.

Appendix I: Normal Neuroimaging.

Appendix II: Brain Atlas.

Appendix III: Sheep Brain Dissection.

Appendix IV: Neuroimaging Principles (with William Copen).

Appendix V: Marterials List.

Key Terms for Self Study.

Index.

Editorial Reviews

…a good addition to any bookshelf...easy to read, with an informal approach.” (Neuroradiology, Vol. 46, No. 9, September 2004)

"...engaging and highly novel presentation...provides a thorough understanding of the central nervous system..." (www.neuro-psychoanalysis.org, 19 April 2004)

"The authors have deployed their years of experience in writing a manual which we would highly recommend to anyone needing to learn functional neuroanatomy for use in a clinical or laboratory setting." (Yale Journal of Biology and Medicine, July 2003)

"…unfolds to the students the principles of Neuroanatomy and… how to investigate and gain knowledge about the human brain." (Journal of Chemical Neuroanatomy, August 2007)

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