Netter's Head and Neck Anatomy for Dentistry E-Book

Author: Neil S. Norton

Publisher: Elsevier Health Sciences

ISBN: 0323462081

Category: Medical

Page: 813

View: 7157

A concise and visual guide to clinically relevant anatomy for dentistry, Netter’s Head and Neck Anatomy for Dentistry is an effective text for class and exam preparation, as well as a quick review in professional practice. Concise text, high-yield tables, clinical correlations, and review questions combine to make this new edition a perfect choice for learning and remembering the need-to-know structures, relationships, and concepts, while beautiful illustrations created in the Netter tradition enhance your visual mastery of the material. You may also be interested in: A companion set of flash cards, Netter's Advanced Head & Neck Anatomy Flash Cards, 3rd Edition. Over 100 multiple-choice questions complete with explanations help you assess your knowledge of the material and prepare for exams. Identify clinically relevant anatomy with Netter illustrations and new art created in the Netter tradition. Concise text and high-yield tables offer fast access to important facts. Procedures coverage gives context and clinical meaning to the anatomy. Expanded, up-to-date coverage on dental implants, cone beam imaging, and mandible osteology. Beautiful new illustrations by Carlos Machado, MD, of the TMJ, articular disc pathology, infratemporal fossa, pterygopalatine fossa, and maxillary artery.

Netter's Advanced Head and Neck Flash Cards

Author: Neil S. Norton

Publisher: Elsevier Health Sciences

ISBN: 0323481965

Category: Medical

Page: 540

View: 5477

Netter's Advanced Head & Neck Anatomy Flash Cards are the perfect portable study tool for quizzing yourself on key anatomic structures and clinical conditions of the head and neck. They accentuate the clinically relevant anatomy through beautiful Netter illustrations and new artwork in the Netter tradition, making for a fast and fun review at any stage of your healthcare career. Cards are cross-referenced to the parent text, Netter's Head and Neck Anatomy for Dentistry, 3rd Edition, and include much of the new art from the textbook. Beautiful, well-known Netter illustrations accentuate the clinically relevant anatomy. Includes additional Imaging, New Art, and Clinical Correlate cards. Perfect for quick, portable study for head and neck and dental anatomy courses. Allow you to quiz yourself on key anatomy terms and test your knowledge of classic presentations of disease.

Head and Neck Anatomy for Dental Medicine

Author: Eric William Baker,Michael Schünke,Erik Schulte,Udo Schumacher

Publisher: Thieme

ISBN: 9781604062090

Category: Medical

Page: 372

View: 5150

Praise for this book: Highly recommended...no other currently available textbook offers an equivalent level of information in one place...[the] illustrations are exquisitely detailed and realistic...a truly outstanding addition to any health care professional's library.--JAMA This anatomy textbook excels at every level and is highly recommended to all students and practitioners involved in treating any aspect of the head and neck. --Journal of Clinical Oncology Head and Neck Anatomy for Dental Medicine combines concise but thorough explanatory text with stunning full-color illustrations to guide the reader through every structure of the head and neck. Its exquisite artwork and detailed coverage make this atlas an essential learning tool and reference for every student and practitioner of dental medicine. It will also be useful for otolaryngologists, speech pathologists, or anyone who deals primarily with the head and neck. Featuring expanded material derived from the bestselling Thieme Atlas of Anatomy series, this one-volume atlas is intuitively arranged to simplify the learning process. Coverage of each region begins with the skeletal framework and then adds the muscles, the vasculature, the nerves, and then finally presents the topographic anatomy for a comprehensive overview. Key features of this atlas: A specific focus on head and neck anatomy aimed directly at students of dental medicine and anyone who must have an understanding of this complex anatomic area More than 800 large, full-color, highly detailed illustrations with clear and thorough labeling and descriptive captions plus schematics to elucidate concepts Over 90 tables summarize key information for review and reference A full chapter devoted to sectional anatomy, including radiographic images to demonstrate anatomy as seen in the clinical setting An innovative, user-friendly format in which each two-page spread presents a self-contained guide to a specific topic Head and Neck Anatomy for Dental Medicine includes access to WinkingSkull.com PLUS, the interactive online study aid, with more than 600 full-color illustrations and radiographs from this and Thieme's bestselling anatomy and radiology publications. Review or test your anatomy knowledge with timed self-tests with instant results using the labels on-and-off function on the illustrations. Teaching anatomy? We have the educational e-product you need. Instructors can use the Thieme Teaching Assistant: Anatomy to download and easily import 2,000+ full-color illustrations to enhance presentations, course materials, and handouts.

BOPOD - Illustrated Anatomy of the Head and Neck

Author: Margaret J. Fehrenbach,Susan W. Herring

Publisher: Elsevier Health Sciences

ISBN: 0323429556

Category:

Page: 352

View: 4185

Known for its top-notch artwork and readable writing style, Illustrated Anatomy of the Head and Neck, 5th Edition, provides dental assisting and dental hygiene students with complete coverage of head and neck anatomy, plus detailed discussions of the temporomandibular joint and its role in dental health, the anatomy of local anesthesia, and the spread of dental infection. Chapters are organized by anatomical systems of study and include expanded review questions that help prepare you for classroom and board examinations. Combine this new edition with its companion title, Illustrated Dental Embryology, Histology, and Anatomy, and you will have a solid foundation of basic scientific knowledge that ties to everyday clinical dental practice. Identification exercises at the end of each chapter ask you to label the different structures to test your knowledge of anatomy. Multiple-choice review questions end each chapter and prepare you for board examinations in dental assisting and dental hygiene. Comprehensive coverage provides a solid foundation in head and neck anatomy, with an in-depth discussion of the TMJ and its role in dental health, plus additional material on the anatomy of local anesthesia and the spread of dental infection. Conversational writing style ensures that you easily comprehend complex anatomy and clinical application. Chapters are organized by anatomical systems of study so that discussions progress logically from overviews of the area to the specifics related to the head and neck, providing a solid foundation for learning. Detailed anatomical illustrations and clear, colorful photographs show models and patients within a clinical setting to support text descriptions and help ensure comprehension. Award-winning and trusted author Margaret Fehrenbach curates cutting-edge content and the latest evidence-based information. Key terms and their phonetic pronunciations are highlighted within the chapter and defined in a back-of-book glossary. A how-to appendix with accompanying photos shows you the steps to perform extraoral and intraoral patient examinations. Learning objectives open each chapter with goals to be accomplished, and serve as checkpoints for comprehension, skills mastery, and exam preparedness. NEW and UPDATED! New content and updated chapter discussions include evidence-based information on local anesthesia administration and temporomandibular joint (TMJ) disorders. EXPANDED! Additional end-of-chapter review questions help you assess strengths and weaknesses — and prepare for classroom and board examinations. EXPANDED and REORGANIZED! Clinical content is now woven into the text discussions and expanded within chapters to help reinforce its application to dental treatment, strengthen your critical thinking skills, and better prepare you for clinical encounters. EXPANDED! 36 removable color flashcards offer on-the-go study, with key images on one side and corresponding labels on the back.

Mosby's Comprehensive Review of Dental Hygiene - E-Book

Author: Michele Leonardi Darby

Publisher: Elsevier Health Sciences

ISBN: 0323291066

Category: Medical

Page: 1040

View: 9476

Your one-stop review for the National Board Dental Hygiene Examination (NBDHE), Mosby's Comprehensive Review of Dental Hygiene, 7th Edition is the most trusted review and study tool on the market. A total of 2,500 review questions including four online timed practice exams -- all with answers and rationales for remediation -- make this book stand out as a student favorite. Already known for its in-depth coverage, an easy-to-use outline format, and expert authorship, this review parallels the NBDHE with case studies, the "testlet" format for community health and research content, an emphasis on computer-based testing, and coverage of dynamic areas such as infection control and local anesthesia administration. Expert author Michele Darby provides the NBDHE review tool you cannot afford to be without! A comprehensive review includes all the necessary content for the NBDHE, with 2,500 review questions including four simulated exams. A logical organization covers the three main areas of the NBDHE: (1) the scientific basis for dental hygiene practice, (2) the provision of clinical dental hygiene services, and (3) community health and research principles. NBDHE-style review questions offer practice and self-assessment relating to key content. A new 350-question examination complete with Components A and B mimics the format of the NBDHE and is included in the back of the book and on the companion Evolve website; it provides answers, rationales, and a timer function. Three additional timed simulated practice examinations are provided on the companion website for additional test-taking experience. Case-based questions prepare you for the case studies and scenarios emphasized on the NBDHE. An outline format allows for easy review and study. Illustrations, diagrams, clinical photographs, and radiographs help in recognizing suspected pathologic processes and interpreting radiographs. Tables and boxes summarize concepts and procedures. Unique! Website tables in each chapter provide a quick reference to key sites for further research and study. Expert authors are leading educators, researchers, and practitioners, each of whom has an in-depth knowledge of what it takes to succeed on the NBDHE. 1,450 NEW practice questions are added to this edition for a more complete review. Updated content reflects changes and advances in areas such as infection control, pharmacology, digital imaging, and local anesthesia administration. Expanded case studies promote critical thinking and provide practice with the complex cases that make up Component B of the examination. NEW full-color photographs, illustrations, and radiographs accurately represent dental conditions. Labeling and identification exercises are included, with electronic flashcards for added vocabulary practice.

Netter's Anatomy Flash Cards E-Book

Author: John T. Hansen

Publisher: Elsevier Health Sciences

ISBN: 0323550789

Category: Medical

Page: 676

View: 4794

Learn the essential anatomy you need to know – quickly and easily! Each flash card in this full-color deck features high-quality Netter art (and several new paintings by Dr. Carlos Machado), numbered labels, and concise comments and clinical notes for the most commonly tested anatomy terms and concepts. Focusing on clinically relevant anatomy, this easy-to-use, portable study tool helps you learn anatomical structures with confidence!

Mosby's Review Questions for the National Board Dental Hygiene Examination - E-Book

Author: Mosby

Publisher: Elsevier Health Sciences

ISBN: 0323226310

Category: Medical

Page: 344

View: 1381

Offering the most realistic NBDHE review and practice available, Mosby's Review Questions for the National Board Dental Hygiene Examination includes both a print book and companion website to prepare you for exam success. In the book, you’ll review with more than 1,250 Component A practice questions — with each answer including a rationale for both correct and incorrect answer options. Online, you can review the same questions plus an additional 420 case-based items related to Component B in 1) practice mode or 2) timed, exam-simulation mode with randomized tests that match the number and distribution of questions on the NBDHE. From a team of dental hygiene experts including lead editor Barbara Bennett, this Q&A resource is an excellent supplement to any NBDHE content review book! More than 1,680 multiple-choice questions provide comprehensive practice spanning the entire NBDHE, with 1,250+ items relating to Component A — more than six times the number of questions on the actual exam! — and 420 case-based questions related to Component B. Rationales accompany each question, fully explaining why each answer choice is either correct or incorrect and thus serving as secondary content review. Distribution of questions matches each category on the NBDHE test specifications, ensuring that you have adequate practice for each content area. An Evolve companion website includes all 1,250+ questions from the book plus additional case studies with color images and accompanying questions, available either in practice mode with instant feedback or in exam-simulation format with results and feedback provided at the end of the exam. A test creator and timer on Evolve generates NBDHE-style tests that mimic the number and distribution of questions on the NBDHE and also provides realistic practice with time management during the exam. 16 detailed case studies on Evolve, each of which includes a patient medical/dental history, completed periodontal chart, oral radiographs, clinical photographs, and 20-35 multiple-choice questions for patients in the five main categories covered on the NBDHE (adult periodontitis, pediatric, geriatric, special needs, and medically compromised). References to text sources make it easy to review or find more information on specific topics.

Illustrated Anatomy of the Head and Neck - E-Book

Author: Margaret J. Fehrenbach,Susan W. Herring

Publisher: Elsevier Health Sciences

ISBN: 0323291082

Category: Medical

Page: 336

View: 3014

Featuring a robust collection of full-color illustrations and photographs, Illustrated Anatomy of the Head and Neck, 4th Edition, provides a complete look at head and neck anatomy, with an emphasis on the specific anatomy of the temporomandibular joint (TMJ). Chapters are organized by anatomical systems, including one covering the anatomical basis of local anesthesia and another on the spread of dental infection. Written by educators Margaret Fehrenbach and Susan Herring, this edition adds new illustrations and cutting-edge, evidence-based information on topics such as caries risk, periodontal disease, local anesthesia administration, and infection control. Combine this book with Illustrated Dental Embryology, Histology, and Anatomy, and you will gain the basic scientific knowledge needed for everyday clinical dental practice. Comprehensive coverage provides a solid foundation in head and neck anatomy, with in-depth discussion of the TMJ and its role in dental health and additional material on the anatomy of local anesthesia and the spread of dental infection. Approachable writing style presents cutting-edge content and the latest evidence-based information in a way that may be easily grasped and applied. More than 400 full-color illustrations and clinical photographs show models and patients within a clinical setting. 28 removable color flashcards offer on-the-go study, with key images on one side and corresponding labels on the back. Identification exercises in each chapter ask you to label the different structures to test your knowledge of anatomy. Multiple-choice review questions in each chapter include a mixture of knowledge- and application-based content, and prepare you for the national board examinations in dental assisting and dental hygiene. Easy-to-read tables and boxes summarize concepts and procedures. Key terms begin each chapter, accompanied by phonetic pronunciations, and are highlighted within the chapter. Learning objectives open each chapter with goals to be accomplished, also serve as checkpoints for comprehension, skills mastery, and study tools in preparation for examinations. A glossary offers quick and handy access to all the key terms and definitions used in the book. Updated content includes evidence-based information on hot topics such as caries risk, periodontal disease, local anesthesia administration, and infection control. NEW! Additional full-color illustrations and photographs support text descriptions and help ensure complete comprehension. Updated review questions are included in every chapter to correlate with new content. A companion Evolve website offers more practice with case studies, image identification, and flashcards.

Head and Neck MRI, An Issue of Magnetic Resonance Imaging Clinics - E-Book

Author: Laurie A. Loevner

Publisher: Elsevier Health Sciences

ISBN: 145574977X

Category: Medical

Page: 245

View: 5552

This issue reviews the state of the art of head and neck imaging, with clear reviews of the role of MRI in the diagnosis and treatment of some of the most common head and neck conditions. Articles discuss imaging of head and neck tumors, head and neck reconstruction for cancer treatment, oral cavity carcinoma and imaging of the TMJ. Reviews cover patterns of perineural spread, MRI applications in temporal bone pathology, MRI of brachial plexus, and imaging of the pediatric neck. Orbital pathology and optic pathways are covered, as well as paranasal sinuses, and sella and parasellar regions.

Local and Regional Flaps of the Head and Neck, An Issue of Oral and Maxillofacial Clinics of North America,

Author: Din Lam

Publisher: Elsevier Health Sciences

ISBN: 0323320392

Category: Medical

Page: 177

View: 9381

Editors Din Lam and Robert Strauss review important areas in Local and Regional Flaps of the Head and Neck. Articles will include: Basic flap design, Palatal island flap, Tongue flap, Facial artery musculomucosal flap /Nasolabial flap, Lip reconstruction, Temporalis system, Submental island flap, Platysmal flap, Cervicofacial flap, Paramedian flap, Supraclavicular/Trapezius system, Pectoralis flap, Latissiums Dorsi flaps, and more!

Atlas of Head and Neck Surgery E-Book

Author: James I. Cohen,Gary L. Clayman

Publisher: Elsevier Health Sciences

ISBN: 1455728470

Category: Medical

Page: 640

View: 338

Atlas of Head and Neck Surgery, by Drs. James I. Cohen and Gary L. Clayman, delivers unparalleled visual guidance and insight to help you master the most important and cutting-edge head and neck procedures. Clear, consistent black-and-white drawings and detailed text lead you through each step of all standard operations, while commentary from leading experts presents alternative techniques – complete with explanations about the differences, nuances, pearls, and pitfalls of each approach. Concise yet complete, this easily accessible text captures groundbreaking techniques such as video-assisted thyroid and parathyroid surgeries; transoral laser surgeries; and robotic surgeries. This surgical technique reference is an ideal resource for planning and performing successful head and neck surgery or preparing for the head and neck portion of the Otolaryngology boards. Understand how to proceed thanks to an abundance of explicit illustrations and detailed text that take you from one step to the next. Quickly find the information you need to make confident decisions. Relevant indications/contraindications, pre-operative considerations, and post operative management are presented in an easily accessible format. Discern the nuances and understand the differences between standard operations and alternate techniques. Experts debate each procedure offering insightful explanations, rationale, and tips for avoiding complications. Master new procedures such as video-assisted thyroid and parathyroid surgeries; transoral laser surgeries; and robotic surgeries. Section editor F. Christopher Holsinger, MD, FACS, is at the forefront of many of these techniques, some of which are being illustrated for the first time here. Learn from some of the very best - Experts from the MD Anderson Cancer Center and the Oregon Health & Science University (OHSU) share their innovative approaches to the surgical techniques and complications management most frequently seen in practice. Understand specific variations in anatomy as they apply to each procedure.

Dento-Alveolar Complications, An Issue of Oral and Maxillofacial Surgery Clinics - E-Book

Author: Dennis-Duke R. Yamashita,James P. McAndrews

Publisher: Elsevier Health Sciences

ISBN: 1455712124

Category: Medical

Page: 136

View: 959

A comprehensive review of dento-alveolar complications for the oral and maxillofacial surgeon! Topics will include bleeding, dento-alveolar infections, infections extending into the neck, osteomyelitis and osteitis, endodontic complications, nerve injuries, local anesthesia, pathology, bone grafting, osteoradionecrosis, bisphosphonate associated jaw necrosis, and much more!

Complications in Head and Neck Surgery E-Book

Author: David Eisele,Richard V. Smith

Publisher: Elsevier Health Sciences

ISBN: 1437719635

Category: Medical

Page: 848

View: 6704

Effectively avoiding, recognizing, and managing complications is integral to your operative success. Let a multidisciplinary team of experts in otolaryngology, plastic surgery, oral and maxillofacial surgery, and general surgery guide you through the full range of complications associated with every type of head and neck procedure . . . so you will be equipped to produce the most favorable outcomes for even the most challenging cases! Expert, comprehensive, multidisciplinary coverage of head and neck complications helps you to safely incorporate new surgical techniques into your practice. An emphasis on complication prevention and recognition assists you in avoiding the "complication cascade." Coverage of both acute and long-term care of patients with head and neck complications prepares you to make effective choices in both instances. A new "Quality of Life" section examines the controversies that often surround selecting one procedure over another, illuminating why certain procedures aren't always best for some patients. A new section on complications of facial plastic and reconstructive surgery equips you to perform these techniques with greater confidence. A consistent, practical chapter format helps you focus on key clinical and surgical considerations. A new, more cohesive full-color illustration program richly captures visual nuances of clinical presentation and operative technique. A bonus CD-ROM allows you to use all of the images from the book in electronic presentations.

Chirurgische Anatomie des Kopf-Hals-Bereiches

Author: J. Krmpotic-Nemanic,W. Draf,J. Helms

Publisher: Springer-Verlag

ISBN: 3662113198

Category: Medical

Page: 334

View: 689

Der klinisch und operativ an Kopf und Hals tätige Arzt hat immer schon den Wunsch gehabt, eine Anatomie dieser Region zur Verfügung zu haben, in der er sich schnell und sachlich orientieren kann. Es gibt zwar eine Reihe sehr guter anatomischer Atlanten und Bücher, doch ist darin häufig eine rasche Orientierung, z.B. intra operationem, durch einen ausführlichen, mehr anato misch ausgerichteten Text erschwert. Außerdem lassen sie die klinischen Be lange vielfach vermissen. Die Hauptautorin dieses Buches ist in der glücklichen Lage, neben ihrer anato mischen Ausbildung und Lehrtätigkeit auch eine klinisch-operative Ausbildung zu besitzen, die sie in einer hervorragenden oto-rhino-Iaryngologischen Schule (SERCER) erworben hat. Aus diesem Grunde konnte sie die Probleme des operie renden Arztes und die Besonderheiten der Zugangswege zu tiefer gelegenen Regionen in die anatomischen Abbildungen hineinarbeiten. Zudem hat sie zwei bekannte Operateure als Co-Autoren gewonnen, die ihr beratend zur Seite standen. - Der Text wurde bewußt knapp gehalten, damit Übersicht und rasche Orientierungsmöglichkeit erhalten blieben. Trotzdem sind alle klinisch wesent lichen Einzelheiten und ihre Variationen dargestellt. Auf diese Weise haben die Autoren einen Weg gefunden, der dem Kliniker und dem Operateur die häufig schwierige Anatomie im Kopf- und Halsbereich anschaulich vermittelt. Sowohl dem Erfahrenen als auch dem Lernenden ist das Studium des Bandes besonders anzuempfehlen. Möge dem Buch ein glücklicher Weg beschieden sein, und möge es die weite Verbreitung in den verschiedenen Fachdisziplinen finden, die ihm gebührt.

Dental Hygiene - E-Book

Theory and Practice

Author: Michele Leonardi Darby,Margaret Walsh

Publisher: Elsevier Health Sciences

ISBN: 143770445X

Category: Medical

Page: 1296

View: 6415

Comprehensive and up to date, Dental Hygiene, 3rd Edition offers complete coverage of today’s dental hygiene skills and theories -- all based on the Human Needs Model for better hygienist/patient communication. With a strong focus on clinical application, each section closely follows the critical thinking and clinical assessment approach that a hygienist must use in the classroom, clinic, and practice. Clinical competencies at the beginning of each chapter provide a clear, quick overview of exactly what you need to know, and procedure boxes with detailed steps and rationales ensure that you understand the reasoning behind each step in the competencies. In addition, new chapters on caries risk assessment and the oral-systemic health connection keep you up to date with today’s major areas of research. Each section takes you from conceptual foundations of dental hygiene through patient assessment, treatment, and evaluation. Scenario boxes challenge you to integrate complex information as you assess, diagnose, plan care, and evaluate the outcome of care. Client Education Issues and Legal, Ethical and Safety Issues boxes inform you of the latest information in these important areas. Critical Thinking exercises provide opportunities for independent thought and problem solving. Tables and boxes build upon and simplify information from the text, making study and review quick and easy. Evolve website contains free online resources, including weblinks, self-assessment quizzes, and professional development worksheets for student review. A reorganized section for Individuals with Special Needs includes chapters on Cleft Palate, Physical Abuse, Blood Diseases, and Mental Illness, all reflecting evidence-based research now available in these areas. New chapters on caries risk assessment and the oral-systemic health connection -- hot topics in today’s dental sciences. New anesthesia guidelines keep you up to date with what's new in pain and anxiety control. Essential resources and websites are now included at the end of each chapter for easy reference. New illustrations provide a fresh, reader-friendly design. Self-assessment quizzes are available online, all case-based to follow the NBDH format. Free online access to the Legal and Ethical Decision Making chapter, including an 'asset center' to assist you with clinical skills.

Essentials of Oral Histology and Embryology - E-Book

A Clinical Approach

Author: Daniel J. Chiego

Publisher: Elsevier Health Sciences

ISBN: 0323291007

Category: Medical

Page: 232

View: 3698

With clear coverage of the anatomy of oral and facial tissues, Essentials of Oral Histology and Embryology: A Clinical Approach, 4th Edition, helps you understand normal orofacial development to prepare you to care for patients with abnormalities or dental pathologies. It provides a strong foundation in oral biology, focusing on the development and structure of cells and tissues, the stages of tooth development and maturation, and the parts of teeth including enamel, dentin, dental pulp, and cementum. New illustrations and discussions of emerging issues keep you current with advances in the dental professions and patient care. Written by Daniel J. Chiego Jr., an experienced educator in oral histology and embryology, this book provides the basic science you need to succeed in the classroom and in clinical practice. Clinically focused content provides essential knowledge of the basics of oral biology with an emphasis on its relationship to clinical practice and a focus on the patient. Full-color art program includes many high-quality illustrations, histographs, micrographs, and clinical photos depicting various stages of development of the oral structures. Clinical Comment and Consider the Patient boxes help you apply information to clinical practice and patient care by describing clinical tips, points of interest, and patient situations. Self-evaluation questions are included at the end of each chapter, helping you review for classroom and national board exams. Key vocabulary is listed at the beginning of each chapter and highlighted in boldface within the text. Suggested readings at the end of each chapter allow you to research classic and new studies. Expert author Daniel Chiego has 40 years of experience in research and education in oral embryology and histology, and has directed the dental and dental hygiene courses of study in these topics at the University of Michigan for more than 15 years. An Evolve companion website provides practice quizzes, vocabulary flashcards, labeling exercises, and links to related websites for further research and study. NEW and UPDATED content on thyroid development and hormones, tooth development, dentin, collagen, and cemental repair incorporates findings from recent studies. UPDATED and EXPANDED art program accurately depicts the anatomy of oral and facial tissues and provides high-quality images to help improve comprehension.