Moore - Clinically Oriented Anatomy, 8th Edition PDF

2 Introduction to Clinically Oriented Anatomy Somatic Nervous System / 57 Computed Tomography / 67 Autonomic Nervous System (Ans) / 57 Ultrasonography / 67 TABLE I.2. Functions of Autonomic Nervous...

2 Introduction to Clinically Oriented Anatomy Somatic Nervous System / 57 Computed Tomography / 67 Autonomic Nervous System (Ans) / 57 Ultrasonography / 67 TABLE I.2. Functions of Autonomic Nervous Magnetic Resonance Imaging / 68 System (Ans) / 65 Nuclear Medicine Imaging / 70 MEDICAL IMAGING TECHNIQUES / 66 Conventional Radiography / 66 APPROACHES TO STUDYING outer covering and may be studied and examined in living individuals via surface anatomy. ANATOMY Surface anatomy is an essential part of the study of regional anatomy. It is specifically addressed in this book in Anatomy is the setting (structure) in which the events (func- “surface anatomy sections” (orange background) that provide tions) of life occur. This book deals mainly with functional knowledge of what lies under the skin and what structures human gross anatomy—the examination of structures of the are perceptible to touch (palpable) in the living body at rest human that can be seen without a microscope. The three and in action. We can learn much by observing the exter- main approaches to studying anatomy are regional, systemic, nal form and surface of the body and by observing or feel- and clinical (or applied), reflecting the body’s organization ing the superficial aspects of structures beneath its surface. and the priorities and purposes for studying it. The aim of this method is to visualize (recall distinct mental images of) structures that confer contour to the surface or are palpable beneath it and, in clinical practice, to distinguish Regional Anatomy any unusual or abnormal findings. In short, surface anatomy Regional anatomy (topographical anatomy) considers the requires a thorough understanding of the anatomy of the organization of the human body as major parts or segments structures beneath the surface. In people with stab wounds, (Fig. I.1): a main body, consisting of the head, neck, and trunk for example, a physician must be able to visualize the deep (subdivided into thorax, abdomen, back, and pelvis/perineum), structures that may be injured. Knowledge of surface anat- and paired upper limbs and lower limbs. All the major parts may omy can also decrease the need to memorize facts because be further subdivided into areas and regions. Regional anat- the body is always available to observe and palpate. omy is the method of studying the body’s structure by focusing Physical examination is the clinical application of sur- attention on a specific part (e.g., the head), area (the face), or face anatomy. Palpation is a clinical technique, used with region (the orbital or eye region); examining the arrangement observation and listening for examining the body. Pal- and relationships of the various systemic structures (muscles, pation of arterial pulses, for instance, is part of a physical nerves, arteries, etc.) within it; and then usually continuing to examination. Students of many of the health sciences will study adjacent regions in an ordered sequence. Outside of this learn to use instruments to facilitate examination of the body Introduction, the regional approach is followed in this book, (such as an ophthalmoscope for observation of features of with each chapter addressing the anatomy of a major part of the eyeballs) and to listen to functioning parts of the body the body. This is the approach usually followed in anatomy (a stethoscope to auscultate the heart and lungs). courses that have a laboratory component involving dissection. Regional study of deep structures and abnormalities in When studying anatomy by this approach, it is important to a living person is now also possible by means of radiographic routinely put the regional anatomy into the context of that of and sectional imaging and endoscopy. Radiographic and adjacent regions, parts, and of the body as a whole. sectional imaging (radiographic anatomy) provides useful Regional anatomy also recognizes the body’s organization information about normal structures in living individuals, dem- by layers: skin, subcutaneous tissue, and deep fascia cov- onstrating the effect of muscle tone, body fluids and pressures, ering the deeper structures of muscles, skeleton, and cavi- and gravity that cadaveric study does not. Diagnostic radiology ties, which contain viscera (internal organs). Many of these reveals the effects of trauma, pathology, and aging on normal deeper structures are partially evident beneath the body’s structures. In this book, most radiographic and many sectional  Introduction to Clinically Oriented Anatomy 3 Major parts of the body models. Prosections, carefully prepared dissections for the demonstration of anatomical structures, are also useful. Head Back Lower limb Neck Abdomen Upper limb However, learning is most efficient and retention is highest Thorax Pelvis/perineum when didactic study is combined with the experience of first- hand dissection—that is, learning by doing. During dissec- tion you observe, palpate, move, and sequentially reveal parts of the body. In 1770, Dr. William Hunter, a distinguished Scottish anatomist and obstetrician, stated: “Dissection alone teaches us where we may cut or inspect the living body with freedom and dispatch.” Systemic Anatomy Systemic anatomy is the study of the body’s organ systems that work together to carry out complex functions. The basic systems and the field of study or treatment of each (in paren- 1 theses) are: 2 The integumentary system (dermatology) consists of the 3 skin (L. integumentum, a covering) and its appendages— hairs, nails, and sweat glands, for example—and the sub- 4 5 cutaneous tissue just beneath it. The skin, an extensive sensory organ, forms the body’s outer, protective covering 6 and container. 7 The skeletal system (osteology) consists of bones and cartilage; it provides our basic shape and support for the 8 9 10 body and is what the muscular system acts on to produce 10 movement. It also protects vital organs such as the heart, Anterior view Posterior view lungs, and pelvic organs. The articular system (arthrology) consists of joints and Regions of lower limb their associated ligaments, connecting the bony parts of 1 = Gluteal region 6 = Anterior leg region the skeletal system and providing the sites at which move- 2 = Anterior thigh region 7 = Posterior leg region ments occur. 3 = Posterior thigh region 8 = Anterior talocrural (ankle) region 4 = Anterior knee region 9 = Posterior talocrural region The muscular system (myology) consists of skeletal mus- 5 = Posterior knee region 10 = Foot region cles that act (contract) to move or position parts of the body (e.g., the bones that articulate at joints), or smooth FIGURE I.1. Major parts of the body and regions of the lower limb. and cardiac muscle that propels, expels, or controls the Anatomy is described relative to the anatomical position illustrated here. flow of fluids and contained substance. The nervous system (neurology) consists of the central nervous system (brain and spinal cord) and the peripheral images are integrated into the chapters where appropriate. nervous system (nerves and ganglia, together with their The medical imaging sections at the end of each chapter pro- motor and sensory endings). The nervous system con- vide an introduction to the techniques of radiographic and sec- trols and coordinates the functions of the organ systems, tional imaging and include series of sectional images that apply enabling the body’s responses to and activities within its to the chapter. Endoscopic techniques (using a insertable flex- environment. The sense organs, including the olfactory ible fiber optic device to examine internal structures, such as organ (sense of smell), eye or visual system (ophthal- the interior of the stomach) also demonstrate living anatomy. mology), ear (sense of hearing and balance—otology), and The detailed and thorough learning of the three-dimensional gustatory organ (sense of taste), are often considered with anatomy of deep structures and their relationships is best the nervous system in systemic anatomy. accomplished initially by dissection. In clinical practice, sur- The circulatory system (angiology) consists of the face anatomy, radiographic and sectional images, endoscopy, cardiovascular and lymphatic systems, which function in and your experience from studying anatomy will combine to parallel to transport the body’s fluids. provide you with knowledge of your patient’s anatomy. The cardiovascular system (cardiology) consists of the The computer is a useful adjunct in teaching regional anat- heart and blood vessels that propel and conduct blood omy because it facilitates learning by allowing interactivity through the body, delivering oxygen, nutrients, and hor- and manipulation of two- and three-dimensional graphic mones to cells and removing their waste products. 4 Introduction to Clinically Oriented Anatomy The lymphatic system is a network of lymphatic vessels Clinical Anatomy that withdraws excess tissue fluid (lymph) from the body’s interstitial (intercellular) fluid compartment, filters it Clinical anatomy (applied anatomy) emphasizes aspects of through lymph nodes, and returns it to the bloodstream. bodily structure and function important in the practice of The alimentary or digestive system (gastroenterology) medicine, dentistry, and the allied health sciences. It incor- consists of the digestive tract from the mouth to the anus, porates the regional and systemic approaches to studying with all its associated organs and glands that function in anatomy and stresses clinical application. ingestion, mastication (chewing), deglutition (swallow- Clinical anatomy often involves inverting or reversing the ing), digestion, and absorption of food and the elimination thought process typically followed when studying regional of the solid waste (feces) remaining after the nutrients or systemic anatomy. For example, instead of thinking, “The have been absorbed. action of this muscle is to... ,” clinical anatomy asks, “How The respiratory system (pulmonology) consists of the air would the absence of this muscle’s activity be manifest?” passages and lungs that supply oxygen to the blood for cel- Instead of noting, “The... nerve provides innervation to this lular respiration and eliminate carbon dioxide from it. The area of skin,” clinical anatomy asks, “Numbness in this area diaphragm and larynx control the flow of air through the indicates a lesion of which nerve?” system, which may also produce tone in the larynx that is Clinical anatomy is exciting to learn because of its role in further modified by the tongue, teeth, and lips into speech. solving clinical problems. The clinical correlation boxes (pop- The urinary system (urology) consists of the kidneys, ularly called “blue boxes,” appearing on a blue background) ureters, urinary bladder, and urethra, which filter blood throughout this book describe practical applications of anat- and subsequently produce, transport, store, and intermit- omy. “Case studies,” such as those on the Clinically Oriented tently excrete urine (liquid waste). Anatomy website (http://thePoint.lww.com/COA7e), are The genital (reproductive) system (gynecology for integral parts of the clinical approach to studying anatomy. females; andrology for males) consists of the gonads (ova- ries and testes) that produce oocytes (eggs) and sperms, the ducts that transport them, and the genitalia that enable their union. After conception, the female repro- The Bottom Line ductive tract nourishes and delivers the fetus. The endocrine system (endocrinology) consists of STUDYING ANATOMY specialized structures that secrete hormones, including Anatomy is the study of the structure of the human body. discrete ductless endocrine glands (such as the thyroid ♦ Regional anatomy considers the body as organized into gland), isolated and clustered cells of the gut and blood segments or parts. ♦ Systemic anatomy sees the body as vessel walls, and specialized nerve endings. Hormones organized into organ systems. ♦ Surface anatomy provides are organic molecules that are carried by the circulatory information about structures that may be observed or system to distant effector cells in all parts of the body. palpated beneath the skin. ♦ Radiographic, sectional, and The influence of the endocrine system is thus as broadly endoscopic anatomy allows appreciation of structures in distributed as that of the nervous system. Hormones influ- living people, as they are affected by muscle tone, body flu- ence metabolism and other processes, such as the men- ids and pressures, and gravity. ♦ Clinical anatomy empha- strual cycle, pregnancy, and parturition (childbirth). sizes application of anatomical knowledge to the practice None of the systems functions in isolation. The passive skel- of medicine. etal and articular systems and the active muscular system col- lectively constitute a supersystem, the locomotor system or apparatus (orthopedics), because they must work together to produce locomotion of the body. Although the structures ANATOMICOMEDICAL directly responsible for locomotion are the muscles, bones, joints, and ligaments of the limbs, other systems are indi- TERMINOLOGY rectly involved as well. The brain and nerves of the nervous system stimulate them to act; the arteries and veins of the cir- Anatomical terminology introduces and makes up a large culatory system supply oxygen and nutrients to and remove part of medical terminology. To be understood, you must waste from these structures; and the sensory organs (espe- express yourself clearly, using the proper terms in the cor- cially vision and equilibrium) play important roles in direct- rect way. Although you are familiar with common, colloquial ing their activities in a gravitational environment. terms for parts and regions of the body, you must learn the In this Introduction, an overview of several systems sig- international anatomical terminology (e.g., axillary fossa nificant to all parts and regions of the body will be provided instead of armpit and clavicle instead of collarbone) that before Chapters 1 through 8 cover regional anatomy in detail. enables precise communication among healthcare profes- Chapter 9 also presents systemic anatomy in reviewing the sionals and scientists worldwide. Health professionals must cranial nerves. also know the common and colloquial terms people are likely  Introduction to Clinically Oriented Anatomy 5 to use when they describe their complaints. Furthermore, and if you learn their meanings and think about them as you you must be able to use terms people will understand when read and dissect, it will be easier to remember their names. explaining their medical problems to them. Abbreviations. Abbreviations of terms are used for brev- The terminology in this book conforms to the new Interna- ity in medical histories and in this and other books, such as in tional Anatomical Terminology. Terminologia Anatomica (TA) tables of muscles, arteries, and nerves. Clinical abbreviations and Terminologia Embryologica (TE) list terms both in Latin are used in discussions and descriptions of signs and symptoms. and as English equivalents (e.g., the common shoulder muscle Learning to use these abbreviations also speeds note taking. is musculus deltoideus in Latin and deltoid in English). Most Common anatomical and clinical abbreviations are provided terms in this book are English equivalents. Official terms are in this text when the corresponding term is introduced—for available at www.unifr.ch/ifaa. Unfortunately, the terminology example, temporomandibular joint (TMJ). The Clinically Ori- commonly used in the clinical arena may differ from the offi- ented Anatomy website (http://thePoint.lww.com/COA7e) cial terminology. Because this discrepancy may be a source provides a list of commonly used anatomical abbreviations. of confusion, this text clarifies commonly confused terms by More extensive lists of common medical abbreviations may placing the unofficial designations in parentheses when the be found in the appendices of comprehensive medical dictio- terms are first used—for example, pharyngotympanic tube naries (e.g., Stedman’s Medical Dictionary, 28th ed.). (auditory tube, eustachian tube) and internal thoracic artery (internal mammary artery). Eponyms, terms incorporating the Anatomical Position names of people, are not used in the new terminology because they give no clue about the type or location of the structures All anatomical descriptions are expressed in relation to one involved. Further, many eponyms are historically inaccurate in consistent position, ensuring that descriptions are not ambig- terms of identifying the original person to describe a structure uous (Figs. I.1 and I.2). One must visualize this position in or assign its function, and do not conform to an international the mind when describing patients (or cadavers), whether standard. Notwithstanding, commonly used eponyms appear they are lying on their sides, supine (recumbent, lying on the in parentheses throughout the book when these terms are first back, face upward), or prone (lying on the abdomen, face used—such as sternal angle (angle of Louis)—since you will downward). The anatomical position refers to the body surely encounter them in your clinical years. Note that epony- position as if the person were standing upright with the: mous terms do not help to locate the structure in the body. head, gaze (eyes), and toes directed anteriorly (forward), The Clinically Oriented Anatomy website (http://thePoint. arms adjacent to the sides with the palms facing anteri- lww.com/COA7e) provides a list of eponymous terms. orly, and Structure of terms. Anatomy is a descriptive science and lower limbs close together with the feet parallel. requires names for the many structures and processes of the body. Because most terms are derived from Latin and Greek, This position is adopted globally for anatomicomedical medical language may seem difficult at first; however, as you descriptions. By using this position and appropriate terminol- learn the origin of terms, the words make sense. For example, ogy, you can relate any part of the body precisely to any other the term gaster is Latin for stomach or belly. Consequently, part. It should also be kept in mind, however, that gravity the esophagogastric junction is the site where the esophagus causes a downward shift of internal organs (viscera) when the connects with the stomach, gastric acid is the digestive juice upright position is assumed. Since people are typically exam- secreted by the stomach, and a digastric muscle is a muscle ined in the supine position, it is often necessary to describe divided into two bellies. the position of the affected organs when supine, making spe- Many terms provide information about a structure’s cific note of this exception to the anatomical position. shape, size, location, or function or about the resemblance of one structure to another. For example, some muscles have Anatomical Planes descriptive names to indicate their main characteristics. Anatomical descriptions are based on four imaginary planes The deltoid muscle, which covers the point of the shoulder, (median, sagittal, frontal, and transverse) that intersect the is triangular, like the symbol for delta, the fourth letter of body in the anatomical position (Fig. I.2): the Greek alphabet. The suffix -oid means “like”; therefore, deltoid means like delta. Biceps means two-headed and tri- The median plane (median sagittal plane), the vertical ceps means three-headed. Some muscles are named accord- plane passing longitudinally through the body, divides the ing to their shape—the piriformis muscle, for example, is body into right and left halves. The plane defines the mid- pear shaped (L. pirum, pear + L. forma, shape or form). line of the head, neck, and trunk where it intersects the Other muscles are named according to their location. The surface of the body. Midline is often erroneously used as temporal muscle is in the temporal region (temple) of the a synonym for the median plane. cranium (skull). In some cases, actions are used to describe Sagittal planes are vertical planes passing through the muscles—for example, the levator scapulae elevates the scap- body parallel to the median plane. Parasagittal is com- ula (L. shoulder blade). Anatomical terminology applies logical monly used but is unnecessary because any plane paral- reasons for the names of muscles and other parts of the body, lel to and on either side of the median plane is sagittal 6 Introduction to Clinically Oriented Anatomy Median plane Frontal (coronal) plane Sagittal plane Transverse (axial) plane Median plane of hand Frontal (coronal) Median plane of plane of feet foot (A) (B) (C) FIGURE I.2. Anatomical planes. The main planes of the body are illustrated. by definition. However, a plane parallel and near to the the long axis of the foot runs horizontally, a transverse sec- median plane may be referred to as a paramedian plane. tion of the foot lies in the frontal plane (Fig. I.2C). Frontal (coronal) planes are vertical planes passing Oblique sections are slices of the body or any of its parts through the body at right angles to the median plane, divid- that are not cut along the previously listed anatomical ing the body into anterior (front) and posterior (back) parts. planes. In practice, many radiographic images and ana- Transverse planes are horizontal planes passing through tomical sections do not lie precisely in sagittal, frontal, or the body at right angles to the median and frontal planes, transverse planes; often they are slightly oblique. dividing the body into superior (upper) and inferior Anatomists create sections of the body and its parts anatomi- (lower) parts. Radiologists refer to transverse planes as cally, and clinicians create them by planar imaging technolo- transaxial, which is commonly shortened to axial planes. gies, such as computerized tomography (CT), to describe Since the number of sagittal, frontal, and transverse planes and display internal structures. is unlimited, a reference point (usually a visible or palpable landmark or vertebral level) is necessary to identify the loca- tion or level of the plane, such as a “transverse plane through Terms of Relationship the umbilicus” (Fig. I.2C). Sections of the head, neck, and and Comparison trunk in precise frontal and transverse planes are symmet- Various adjectives, arranged as pairs of opposites, describe rical, passing through both the right and left members of the relationship of parts of the body or compare the position paired structures, allowing some comparison. of two structures relative to each other (Fig. I.4). Some of The main use of anatomical planes is to describe sections these terms are specific for comparisons made in the ana- (Fig. I.3): tomical position, or with reference to the anatomical planes: Longitudinal sections run lengthwise or parallel to the Superior refers to a structure that is nearer the vertex, long axis of the body or of any of its parts, and the term the topmost point of the cranium (Mediev. L., skull). Cranial applies regardless of the position of the body. Although relates to the cranium and is a useful directional term, mean- median, sagittal, and frontal planes are the standard (most ing toward the head or cranium. Inferior refers to a struc- commonly used) longitudinal sections, there is a 180° ture that is situated nearer the sole of the foot. Caudal range of possible longitudinal sections. (L. cauda, tail) is a useful directional term that means toward Transverse sections, or cross sections, are slices of the feet or tail region, represented in humans by the coccyx the body or its parts that are cut at right angles to the (tail bone), the small bone at the inferior (caudal) end of the longitudinal axis of the body or of any of its parts. Because vertebral column.  Introduction to Clinically Oriented Anatomy 7 Longitudinal Transverse section Oblique section section (A) (B) (C) FIGURE I.3. Sections of the limbs. Sections may be obtained by anatomical sectioning or medical imaging techniques. Posterior (dorsal) denotes the back surface of the body Superficial, intermediate, and deep describe the posi- or nearer to the back. Anterior (ventral) denotes the front tion of structures relative to the surface of the body or the surface of the body. Rostral is often used instead of anterior relationship of one structure to another underlying or overly- when describing parts of the brain; it means toward the ros- ing structure. trum (L. for beak); however, in humans it denotes nearer the External means outside of or farther from the center of anterior part of the head (e.g., the frontal lobe of the brain is an organ or cavity, while internal means inside or closer to rostral to the cerebellum). the center, independent of direction. Medial is used to indicate that a structure is nearer to the Proximal and distal are used when contrasting positions median plane of the body. For example, the 5th digit of the hand nearer to or farther from the attachment of a limb or the (little finger) is medial to the other digits. Conversely, lateral central aspect of a linear structure, respectively. stipulates that a structure is farther away from the median plane. The 1st digit of the hand (thumb) is lateral to the other digits. Terms of Laterality Dorsum usually refers to the superior aspect of any Paired structures having right and left members (e.g., the part that protrudes anteriorly from the body, such as the kidneys) are bilateral, whereas those occurring on one side dorsum of the tongue, nose, penis, or foot. It is also used only (e.g., the spleen) are unilateral. Designating whether to describe the posterior surface of the hand, opposite the you are referring specifically to the right or left member of palm. Because the term dorsum may refer to both superior bilateral structures can be critical, and is a good habit to begin and posterior surfaces in humans, the term is easier to under- at the outset of one’s training to become a health professional. stand if one thinks of a quadripedal plantigrade animal that Something occurring on the same side of the body as another walks on its palms and soles, such as a bear. The sole is the structure is ipsilateral; the right thumb and right great (big) inferior aspect or bottom of the foot, opposite the dorsum, toe are ipsilateral, for example. Contralateral means occur- much of which is in contact with the ground when standing ring on the opposite side of the body relative to another struc- barefoot. The surface of the hands, the feet, and the digits of ture; the right hand is contralateral to the left hand. both corresponding to the dorsum is the dorsal surface, the surface of the hand and fingers corresponding to the palm is the palmar surface, and the surface of the foot and toes Terms of Movement corresponding to the sole is the plantar surface. Various terms describe movements of the limbs and other Combined terms describe intermediate positional arrange- parts of the body (Fig. I.5). Most movements are defined ments: inferomedial means nearer to the feet and median in relationship to the anatomical position, with movements plane—for example, the anterior parts of the ribs run infero- occurring within, and around axes aligned with, specific ana- medially; superolateral means nearer to the head and far- tomical planes. While most movements occur at joints where ther from the median plane. two or more bones or cartilages articulate with one another, Other terms of relationship and comparisons are inde- several non-skeletal structures exhibit movement (e.g., tongue, pendent of the anatomical position or the anatomical planes, lips, eyelids). Terms of movement may also be considered in relating primarily to the body’s surface or its central core: pairs of oppositing movements: 8 Introduction to Clinically Oriented Anatomy * Superficial Superior (cranial) Palmar vs. Dorsal Nearer to surface Nearer to head Anterior hand (palm) The muscles of the arm The heart is superior Posterior hand (dorsum) are superficial to its to the stomach. bone (humerus). Dorsal Palmar surface surface * Intermediate Dorsum Palm Between a superficial and a deep structure The biceps muscle is intermediate between the skin and the humerus. Plantar vs. Dorsal Inferior foot surface (sole) * Deep Superior foot surface (dorsum) Farther from surface The humerus is deep Dorsal Plantar to the arm muscles. surface surface Median plane Dorsum Sole Coronal plane Medial Nearer to median plane The 5th digit (little finger) is on the medial * Proximal side of the hand. Nearer to trunk or point of origin (e.g., of a limb) Lateral The elbow is proximal to Farther from median the wrist, and the prox- plane imal part of an artery is its beginning. The 1st digit (thumb) is on the lateral side of the hand. * Distal Farther from trunk or point of origin (e.g., of a limb) The wrist is distal to the elbow, and the distal Posterior (dorsal) part of the upper limb is the hand. Nearer to back The heel is posterior to the toes. Anterior (ventral) Nearer to front The toes are anterior to the ankle. Key Terms applied to the entire body Terms specific for hands and feet Inferior (caudal) * Terms independent of anatomical position Nearer to feet The stomach is inferior to the heart. FIGURE I.4. Terms of relationship and comparison. These terms describe the position of one structure relative to another.  Extension Flexion Extension Flexion Flexion Extension Flexion Extension Extension Flexion (A) Flexion and extension of upper limb at Flexion and extension of forearm at Flexion and extension of vertebral shoulder joint and lower limb at hip joint elbow joint and of leg at knee joint column at intervertebral joints Extension ion Flexion Supination Pronation Flexion n Extension Opposition Reposition (B) Flexion and extension Flexion and extension (C) Opposition and reposition of thumb (D) Pronation and supination of hand at wrist joint of digits (fingers) at and little finger at carpometacarpal of forearm at radio-lnar metacarpophalangeal and joint of thumb combined with flexion at joints interphalangeal joints metacarpophalangeal joints Adduction Abduction Extension Flexion Abduction Adduction Lateral Medial abduction abduction (F) The thumb is rotated 90° relative to other structures. Abduction and (E) Abduction and adduction Abduction of 3rd digit at adduction at metacarpophalangeal joint occurs in a sagittal plane; of 2nd, 4th, and 5th metacarpophalangeal flexion and extension at metacarpophalangeal and interphalangeal digits at metacarpo- joint joints occurs in frontal planes, opposite to these movements at all phalangeal joints other joints. FIGURE I.5. Terms of movement. These terms describe movements of the limbs and other parts of the body; most movements take place at joints, where two or more bones or cartilages articulate with one another. 10 Introduction to Clinically Oriented Anatomy Lateral (external) Dorsiflexion rotation Medial Abduction (internal) rotation Plantarflexion Dorsiflexion and plantarflexion of foot at ankle joint Adduction Lateral rotation Medial rotation Eversion Inversion Abduction Adduction Circumduction (G) Abduction and adduction of right limbs and (H) Circumduction (circular movement) of (I) Inversion and eversion of foot at rotation of left limbs at glenohumeral and hip lower limb at hip joint subtalar and transverse tarsal joints joints, respectively Lateral bending Rotation of head and neck Rotation of upper trunk, neck, and head Elevation Depression (K) Elevation and depression of shoulders (J) Lateral bending (lateral flexion) of trunk and rotation of upper trunk, neck, and head Retraction Retrusion Protrusion Protraction (L) Protrusion and retrusion of jaw at temporomandibular joints (M) Protraction and retraction of scapula on thoracic wall FIGURE I.5. (Continued)  Introduction to Clinically Oriented Anatomy 11 Flexion and extension movements generally occur in sag- and across the anterior aspect of the ulna (the other long bone ittal planes around a transverse axis (Fig. I.5A & B). Flex- of the forearm) while the proximal end of the radius rotates in ion indicates bending or decreasing the angle between the place (Fig. I.5D). Pronation rotates the radius medially so that bones or parts of the body. For most joints (e.g., elbow), flex- the palm of the hand faces posteriorly and its dorsum faces ante- ion involves movement in an anterior direction. Extension riorly. When the elbow joint is flexed, pronation moves the hand indicates straightening or increasing the angle between the so that the palm faces inferiorly (e.g., placing the palms flat on a bones or parts of the body. Extension usually occurs in a pos- table). Supination is the opposite rotational movement, rotat- terior direction. The knee joint, rotated 180° to other joints, is ing the radius laterally and uncrossing it from the ulna, return- exceptional in that flexion of the knee involves posterior move- ing the pronated forearm to the anatomical position. When the ment and extension involves anterior movement. Dorsiflex- elbow joint is flexed, supination moves the hand so that the palm ion describes flexion at the ankle joint, as occurs when walking faces superiorly. (Memory device: You can hold soup in the palm uphill or lifting the front of the foot and toes off the ground of your hand when the flexed forearm is supinated but are prone (Fig. I.5I). Plantarflexion bends the foot and toes toward the [likely] to spill it if the forearm is then pronated!) ground, as when standing on your toes. Extension of a limb or Eversion moves the sole of the foot away from the median part beyond the normal limit—hyperextension (overexten- plane, turning the sole laterally (Fig. I.5I). When the foot is sion)—can cause injury, such as “whiplash” (i.e., hyperexten- fully everted it is also dorsiflexed. Inversion moves the sole sion of the neck during a rear-end automobile collision). of the foot toward the median plane (facing the sole medi- Abduction and adduction movements generally occur in a ally). When the foot is fully inverted it is also plantarflexed. frontal plane around an anteroposterior axis (Fig. I.5E & G). Pronation of the foot actually refers to a combination of ever- Except for the digits, abduction means moving away from sion and abduction that results in lowering of the medial the median plane (e.g., when moving an upper limb laterally margin of the foot (the feet of an individual with flat feet away from the side of the body) and adduction means mov- are pronated), and supination of the foot generally implies ing toward it. In abduction of the digits (fingers or toes), the movements resulting in raising the medial margin of the foot, term means spreading them apart—moving the other fingers a combination of inversion and adduction. away from the neutrally positioned 3rd (middle) finger or Opposition is the movement by which the pad of the 1st moving the other toes away from the neutrally positioned 2nd digit (thumb) is brought to another digit pad (Fig. I.5C). This toe. The 3rd finger and 2nd toe medially or laterally abduct movement is used to pinch, button a shirt, and lift a teacup by away from the neutral position. Adduction of the digits is the handle. Reposition describes the movement of the 1st digit the opposite—bringing the spread fingers or toes together, from the position of opposition back to its anatomical position. toward the neutrally positioned 3rd finger or 2nd toe. Right Protrusion is a movement anteriorly (forward) as in and left lateral flexion (lateral bending) are special forms of protruding the mandible (chin), lips, or tongue (Fig. I.5L). abduction for only the neck and trunk (Fig. I.5J). The face Retrusion is a movement posteriorly (backward), as in and upper trunk are directed anteriorly as the head and/or retruding the mandible, lips, or tongue. The similar terms shoulders tilt to the right or left side, causing the midline of protraction and retraction are used most commonly for the body itself to become bent sideways. This is a compound anterolateral and posteromedial movements of the scapula movement occurring between many adjacent vertebrae. on the thoracic wall, causing the shoulder region to move As you can see by noticing the way the thumbnail faces anteriorly and posteriorly (Fig. I.5M). (laterally instead of posteriorly in the anatomical posi- Elevation raises or moves a part superiorly, as in elevat- tion), the thumb is rotated 90° relative to the other digits ing the shoulders when shrugging, the upper eyelid when (Fig. I.5F). Therefore, the thumb flexes and extends in the opening the eye, or the tongue when pushing it up against frontal plane and abducts and adducts in the sagittal plane. the palate (roof of mouth) (Fig. I.5K). Depression lowers or Circumduction is a circular movement that involves moves a part inferiorly, as in depressing the shoulders when sequential flexion, abduction, extension, and adduction (or standing at ease, the upper eyelid when closing the eye, or in the opposite order) in such a way that the distal end of the pulling the tongue away from the palate. part moves in a circle (Fig. I.5H). Circumduction can occur at any joint at which all the above-mentioned movements are possible (e.g., the shoulder and hip joints). Rotation involves turning or revolving a part of the body The Bottom Line around its longitudinal axis, such as turning one’s head to ANATOMICOMEDICAL TERMINOLOGY face sideways (Fig. I.5G). Medial rotation (internal rotation) brings the anterior surface of a limb closer to the median Anatomical terms are descriptive terms standardized in an plane, whereas lateral rotation (external rotation) takes the international reference guide, Terminologia Anatomica (TA). anterior surface away from the median plane. These terms, in English or Latin, are used worldwide. ♦ Pronation and supination are the rotational movements of Colloquial terminology is used by—and to communicate the forearm and hand that swing the distal end of the radius (the with—lay people. ♦ Eponyms are often used in clinical lateral long bone of the forearm) medially and laterally around  Introduction to Clinically Oriented Anatomy 23 VASCULATURE AND INNERVATION OF BONES Bones are richly supplied with blood vessels. Most appar- Articular cartilage ent are the nutrient arteries (one or more per bone) that arise as independent branches of adjacent arteries outside Epiphysial line the periosteum and pass obliquely through the compact Epiphysial artery bone of the shaft of a long bone via nutrient foramina. The nutrient artery divides in the medullary cavity into Metaphysial artery longitudinal branches that proceed toward each end, sup- plying the bone marrow, spongy bone, and deeper portions Periosteum of the compact bone (Fig. I.15). However, many small (peeled back) branches from the periosteal arteries of the periosteum are Vein responsible for nourishment of most of the compact bone. Consequently, a bone from which the periosteum has been Periosteal nerve removed dies. Periosteal artery Blood reaches the osteocytes (bone cells) in the compact bone by means of haversian systems or osteons (micro- Compact bone with haversian systems scopic canal systems) that house small blood vessels. The ends of the bones are supplied by metaphysial and epiphysial Lymphatic vessel arteries that arise mainly from the arteries that supply the Nutrient artery joints. In the limbs, these arteries are typically part of a peri- and vein articular arterial plexus, which surrounds the joint, ensur- Longitudinal branch ing blood flow distal to the joint regardless of the position of nutrient artery assumed by the joint. Veins accompany arteries through the nutrient foramina. Medullary cavity Many large veins also leave through foramina near the articu- FIGURE I.15. Vasculature and innervation of a long bone. lar ends of the bones. Bones containing red bone marrow have numerous large veins. Lymphatic vessels are also abun- dant in the periosteum. The seam formed during this fusion process (synostosis) Nerves accompany blood vessels supplying bones. The is particularly dense and is recognizable in sectioned bone periosteum is richly supplied with sensory nerves—perios- or radiographs as an epiphysial line (Fig. I.15). The epi- teal nerves—that carry pain fibers. The periosteum is espe- physial fusion of bones occurs progressively from puberty cially sensitive to tearing or tension, which explains the acute to maturity. Ossification of short bones is similar to that of pain from bone fractures. Bone itself is relatively sparsely the primary ossification center of long bones, and only one supplied with sensory endings. Within bones, vasomotor short bone, the calcaneus (heel bone), develops a second- nerves cause constriction or dilation of blood vessels, regu- ary ossification center. lating blood flow through the bone marrow. BONES them for bone fragments in radiographs and other medi- cal images. Accessory (Supernumerary) Bones Accessory (supernumerary) bones develop when Heterotopic Bones additional ossification centers appear and form Bones sometimes form in soft tissues where they extra bones. Many bones develop from several cen- are not normally present (e.g., in scars). Horse rid- ters of ossification, and the separate parts normally fuse. ers often develop heterotopic bones in their thighs Sometimes one of these centers fails to fuse with the main (rider’s bones), probably because of chronic muscle strain bone, giving the appearance of an extra bone. Careful study resulting in small hemorrhagic (bloody) areas that undergo shows that the apparent extra bone is a missing part of the calcification and eventual ossification. main bone. Circumscribed areas of bone are often seen along the sutures of the cranium where the flat bones abut, par- ticularly those related to the parietal bone (see Chapter 7). Trauma to Bone and Bone Changes These small, irregular, worm-like bones are sutural Bones are living organs that cause pain when bones (wormian bones). It is important to know that acces- injured, bleed when fractured, remodel in rela- sory bones are common in the foot, to avoid mistaking tionship to stresses placed on them, and change 24 Introduction to Clinically Oriented Anatomy Unbroken Broken Newly-formed collar of callus Normal bone Remodeled collar of callus Bone density reduced Osteoporotic bone Healed FIGURE BI.5. FIGURE BI.4. Sternal Puncture with age. Like other organs, bones have blood vessels, lym- Examination of bone marrow provides valuable phatic vessels, and nerves, and they may become diseased. information for evaluating hematological (blood) Unused bones, such as in a paralyzed limb, atrophy diseases. Because it lies just beneath the skin (i.e., (decrease in size). Bone may be absorbed, which occurs in is subcutaneous) and is easily accessible, the sternum the mandible when teeth are extracted. Bones hypertrophy (breast bone) is a commonly used site for harvesting bone (enlarge) when they support increased weight for a long marrow. During a sternal puncture, a wide-bore (large period. diameter) needle is inserted through the thin cortical bone Trauma to a bone may break it. For the fracture to heal into the spongy bone. A sample of red bone marrow is aspi- properly, the broken ends must be brought together, approx- rated with a syringe for laboratory examination. Bone mar- imating their normal position. This is called reduction of a row transplantation is sometimes performed in the fracture. During bone healing, the surrounding fibroblasts treatment of leukemia. (connective tissue cells) proliferate and secrete collagen, which forms a collar of callus to hold the bones together Bone Growth and Assessment (Fig. BI.4). Bone remodeling occurs in the fracture area, of Bone Age and the callus calcifies. Eventually, the callus is resorbed and replaced by bone. After several months, little evidence Knowledge of the sites where ossification centers of the fracture remains, especially in young people. Frac- occur, the times of their appearance, the rates at tures are more common in children than in adults because which they grow, and the times of fusion of the sites of the combination of their slender, growing bones and care- (times when synostosis occurs) is important in clinical medi- free activities. Fortunately, many of these breaks are green- cine, forensic science, and anthropology. A general index of stick fractures (incomplete breaks caused by bending of the growth during infancy, childhood, and adolescence is indi- bones). Fractures in growing bones heal faster than those in cated by bone age, as determined from radiographs (negative adult bones. images on X-ray films). The age of a young person can be determined by studying the ossification centers in bones. The main criteria are: (1) the appearance of calcified mate- Osteoporosis rial in the diaphysis and/or epiphyses and (2) the disappear- During the aging process, the organic and inor- ance of the radiolucent (dark) line representing the ganic components of bone both decrease, often epiphysial plate (absence of this line indicates that epiphysial resulting in osteoporosis, a reduction in the quan- fusion has occurred; fusion occurs at specific times for each tity of bone, or atrophy of skeletal tissue (Fig. BI.5). Hence, epiphysis). The fusion of epiphyses with the diaphysis occurs the bones become brittle, lose their elasticity, and fracture 1 to 2 years earlier in girls than in boys. Determining bone easily. Bone scanning is an imaging method used to assess age can be helpful in predicting adult height in early- or late- normal and diminished bone mass (see the section on maturing adolescents. Assessment of bone age also helps Medical Imaging Techniques at the end of this establish the approximate age of human skeletal remains in Introduction). medicolegal cases.  Introduction to Clinically Oriented Anatomy 25 Effects of Disease and Diet could be mistaken for a fracture, and separation of an epiph- ysis could be interpreted as a displaced piece of a fractured on Bone Growth bone. Knowing the patient’s age and the location of epiphy- Some diseases produce early epiphysial fusion (ossi- ses can prevent these anatomical errors. The edges of the fication time) compared with what is normal for the diaphysis and epiphysis are smoothly curved in the region of person’s chronological age; other diseases result in the epiphysial plate. Bone fractures always leave a sharp, delayed fusion. The growing skeleton is sensitive to relatively often uneven edge of bone. An injury that causes a fracture slight and transient illnesses and to periods of malnutrition. in an adult usually causes the displacement of an epiphysis in Proliferation of cartilage at the metaphyses slows down dur- a child. ing starvation and illness, but the degeneration of cartilage cells in the columns continues, producing a dense line of pro- visional calcification. These lines later become bone with Avascular Necrosis thickened trabeculae, or lines of arrested growth. Loss of arterial supply to an epiphysis or other parts of a bone results in the death of bone tissue— Displacement and Separation avascular necrosis (G. nekrosis, deadness). After every fracture, small areas of adjacent bone undergo necrosis. of Epiphyses In some fractures, avascular necrosis of a large fragment of Without knowledge of bone growth and the appear- bone may occur. A number of clinical disorders of epiphyses ance of bones in radiographic and other diagnostic in children result from avascular necrosis of unknown etiology images at various ages, a displaced epiphysial plate (cause). These disorders are referred to as osteochondroses. The Bottom Line ment, such as the epiphysial plates between the epiphysis and diaphysis of a growing long bone; others allow only slight movement, such as teeth within their sockets; and some are CARTILAGE AND BONES freely movable, such as the glenohumeral (shoulder) joint. The skeletal system can be divided into the axial (bones of the head, neck, and trunk) and appendicular skeletons (bones CLASSIFICATION OF JOINTS of the limbs). The skeleton itself is composed of several types of tissue: ♦ cartilage, a semirigid connective tissue; ♦ bone, Three classes of joints are described, based on the manner or a hard form of connective tissue that provides support, type of material by which the articulating bones are united. protection, movement, storage (of certain electrolytes), and 1. The articulating bones of synovial joints are united by a synthesis of blood cells; ♦ periosteum, which surrounds joint (articular) capsule (composed of an outer fibrous bones, and perichondrium, which surrounds cartilage, pro- layer lined by a serous synovial membrane) span- vide nourishment for these tissues and are the sites of new ning and enclosing an articular cavity. The joint cavity cartilage and bone formation. Two types of bone, spongy of a synovial joint, like the knee, is a potential space that and compact, are distinguished by the amount of solid mat- contains a small amount of lubricating synovial fluid, ter and the size and number of spaces they contain. Bones secreted by the synovial membrane. Inside the capsule, can be classified as long, short, flat, irregular, or sesamoid. articular cartilage covers the articulating surfaces of the Standard terms for specific bone markings and features are bones; all other internal surfaces are covered by synovial used when describing the structure of individual bones. membrane. The bones in Figure I.16A, normally closely Most bones take many years to grow. Bones grow apposed, have been pulled apart for demonstration, and through the processes of: ♦ intramembraneous ossifica- the joint capsule has been inflated. Consequently the tion, in which mesenchymal bone models are formed during normally potential joint cavity is exaggerated. The perios- the embryonic and prenatal periods, and ♦ endochon- teum investing the participating bones external to the joint dral ossification, in which cartilage models are formed blends with the fibrous layer of the joint capsule. during the fetal period, with bone subsequently replacing 2. The articulating bones of fibrous joints are united by most of the cartilage after birth. fibrous tissue. The amount of movement occurring at a fibrous joint depends in most cases on the length of the fibers uniting the articulating bones. The sutures of the cranium are examples of fibrous joints (Fig. I.16B). These Joints bones are close together, either interlocking along a wavy Joints (articulations) are unions or junctions between two line or overlapping. A syndesmosis type of fibrous joint or more bones or rigid parts of the skeleton. Joints exhibit a unites the bones with a sheet of fibrous tissue, either a lig- variety of forms and functions. Some joints have no move- ament or a fibrous membrane. Consequently, this type of 26 Introduction to Clinically Oriented Anatomy Periosteum Femur Ligament Synovial membrane Joint cavity (containing synovial fluid) Fibrous capsule Joint cavity Joint Articular Meniscus capsule cartilage Synovial membrane Infrapatellar fat pad Compact Tibia bone (A) Synovial joint Schematic model Knee joint Suture Diploë (spongy Articular Intervertebral disc bone between Compact cartilage two layers of bone compact bone) Head of femur Ulna Epiphysial Coronal plate suture Radius Body of Femur vertebra Interosseous membrane Primary Secondary (C) Cartilaginous joints Suture Syndesmosis (B) Fibrous joints FIGURE I.16. Three classes of joint. Examples of each class are shown. A. Two models demonstrating basic features of a synovial joint. joint is partially movable. The interosseous membrane in united by hyaline cartilage, which permits slight bending the forearm is a sheet of fibrous tissue that joins the radius during early life. Primary cartilaginous joints are usually and ulna in a syndesmosis. A dento-alveolar syndesmo- temporary unions, such as those present during the devel- sis (gomphosis or socket) is a fibrous joint in which a peg- opment of a long bone (Figs. I.14 and I.16C), where the bony like process fits into a socket articulation between the root epiphysis and the shaft are joined by an epiphysial plate. of the tooth and the alveolar process of the jaw. Mobility Primary cartilaginous joints permit growth in the length of of this joint (a loose tooth) indicates a pathological state a bone. When full growth is achieved, the epiphysial plate affecting the supporting tissues of the tooth. However, converts to bone and the epiphyses fuse with the diaphy- microscopic movements here give us information (via the sis. Secondary cartilaginous joints, or symphyses, are sense of proprioception) about how hard we are biting or strong, slightly movable joints united by fibrocartilage. clenching our teeth and whether we have a particle stuck The fibrocartilaginous intervertebral discs (Fig. I.16C) between our teeth. between the vertebrae consist of binding connective tis- 3. The articulating structures of cartilaginous joints are sue that joins the vertebrae together. Cumulatively, these united by hyaline cartilage or fibrocartilage. In primary joints provide strength and shock absorption as well as cartilaginous joints, or synchondroses, the bones are considerable flexibility to the vertebral column (spine).