Introduction to Human anatomyHuman anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut"), which, with human physiology and biochemistry, is a complementary basic medical science, is primarily the scientific study of the morphology of the human body.
History
The development of anatomy as a science extends from the earliest examinations of sacrificial victims to the sophisticated analyses of the body performed by modern scientists. It has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. The field of Human Anatomy has a prestigious history, and is considered to be the most prominent of the biological sciences of the 19th and early 20th centuries. Methods have also improved dramatically, advancing from examination of animals through dissection of cadavers to technologically complex techniques developed in the 20th century.
Anatomy is one of the cornerstones of a doctor’s medical education. Despite being a persistent portion of teaching from at least the renaissance, the format and the amount of information being taught has evolved and changed along with the demands of the profession. What is being taught today may differ in content significantly from the past but the methods used to teach this have not really changed that much. For example all the famous public dissections of the Middle Ages and early renaissance were in fact prosections. Prosection is the direction in which many current medical schools are heading in order to aid the teaching of anatomy and some argue that dissection is better. However looking at results of post graduate exams, medical schools (specifically Birmingham) that use prosection as opposed to dissection do very well in these examinations. This would suggest that prosection can fit very well into the structure of modern medical training.
Ancient anatomyCharaka is referred to as the Father of Anatomy.
1. Egypt
The study of anatomy begins at least as early as 1600 BCE, the date of the Edwin Smith Surgical Papyrus. This treatise shows that the heart, its vessels, liver, spleen, kidneys, hypothalamus, uterus and bladder were recognized, and that the blood vessels were known to emanate from the heart. Other vessels are described, some carrying air, some mucus, and two to the right ear are said to carry the "breath of life", while two to the left ear the "breath of death". The Ebers papyrus (c. 1550 BCE) features a treatise on the heart. It notes that the heart is the center of the blood supply, with vessels attached for every member of the body. The Egyptians seem to have known little about the function of the kidneys and made the heart the meeting point of a number of vessels which carried all the fluids of the body – blood, tears, urine and sperm.
2. Greece
The earliest medical scientist of whose works any great part survives today is Hippocrates, a Greek physician active in the late 5th and early 4th centuries BCE (460 - 377 BCE). His work demonstrates a basic understanding of musculoskeletal structure, and the beginnings of understanding of the function of certain organs, such as the kidneys. Much of his work, however, and much of that of his students and followers later, relies on speculation rather than empirical observation of the body.
One of the greatest achievements of Hippocrates was that he was the first to discover the tricuspid valve of the heart and its function which he documented in the treatise On the Heart in the Hippocratic Corpus. Later anatomists knew the function of the tricuspid valve after reading the Hippocratic Corpus.
In the 4th century BCE, Aristotle and several contemporaries produced a more empirically founded system, based animal dissection. Around this time, Praxagoras is credited as the first to identify the difference between arteries and veins, and the relations between organs are described more accurately than in previous works.
The first use of human cadavers for anatomical research occurred later in the 4th century BCE when Herophilos and Erasistratus gained permission to perform live dissections, or vivisection, on criminals in Alexandria under the auspices of the Ptolemaic dynasty. Herophilos in particular developed a body of anatomical knowledge much more informed by the actual structure of the human body than previous works had been.
3. Galen
The final major anatomist of ancient times was Galen, active in the 2nd century. He compiled much of the knowledge obtained by previous writers, and furthered the inquiry into the function of organs by performing vivisection on animals. Due to a lack of readily available human specimens, discoveries through animal dissection were broadly applied to human anatomy as well. His collection of drawings, based mostly on dog anatomy, became the anatomy textbook for 1500 years. The original text is long gone, and his work was only known to the Renaissance doctors through the careful custody of Arabic medicine.
Medieval anatomyAfter the fall of the Roman Empire, the study of anatomy became stagnant in Christian Europe but flourished in the medieval Islamic world, where Muslim physicians and Muslim scientists contributed heavily to medieval learning and culture. The Persian physician Avicenna (980-1037) absorbed the Galenic teachings on anatomy and expanded on them in The Canon of Medicine (1020s), which was very influential throughout the Islamic world and Christian Europe. The Canon remained the most authoritative book on anatomy in the Islamic world until Ibn al-Nafis in the 13th century, though the book continued to dominate European medical education for even longer until the 16th century.
The Arabian physician Ibn Zuhr (Avenzoar) (1091–1161) was the first physician known to have carried out human dissections and postmortem autopsy. He proved that the skin disease scabies was caused by a parasite, a discovery which upset the theory of humorism supported by Hippocrates and Galen. The removal of the parasite from the patient's body did not involve purging, bleeding, or any other traditional treatments associated with the four humours.
In the 12th century, Saladin's physician Ibn Jumay was also one of the first to undertake human dissections, and he made an explicit appeal for other physicians to do so as well. During a famine in Egypt in 1200, Abd-el-latif observed and examined a large number of skeletons, and he discovered that Galen was incorrect regarding the formation of the bones of the lower jaw and sacrum.
Ibn al-Nafis
The Arabian physician Ibn al-Nafis (1213–1288) was one of the earliest proponents of human dissection and postmortem autopsy, and in 1242, he was the first to describe the pulmonary circulation and coronary circulation of the blood, which form the basis of the circulatory system, for which he is considered the father of the theory of circulation. Ibn al-Nafis also described the earliest concept of metabolism, and developed new systems of anatomy and physiology to replace the Avicennian and Galenic doctrines, while discrediting many of their erroneous theories on the four humours, pulsation, bones, muscles, intestines, sensory organs, bilious canals, esophagus, stomach, and the anatomy of almost every other part of the human body.
Early modern anatomy1. 14th to 16th centuries
The works of Galen and Avicenna, especially The Canon of Medicine which incorporated the teachings of both, were translated into Latin, and the Canon remained the most authoritative text on anatomy in European medical education until the 16th century.
The first major development in anatomy in Christian Europe, since the fall of Rome, occurred at Bologna in the 14th to 16th centuries, where a series of authors dissected cadavers and contributed to the accurate description of organs and the identification of their functions. Prominent among these anatomists were Mondino de Liuzzi and Alessandro Achillini.
The first challenges to the Galenic doctrine in Europe occurred in the 16th century. Thanks to the printing press, all over Europe a collective effort proceeded to circulate the works of Galen and Avicenna, and later publish criticisms on their works. Vesalius was the first to publish a treatise, De humani corporis fabrica, that challenged Galen "drawing for drawing" travelling all the way from Leuven to Padua for permission to dissect victims from the gallows without fear of persecution. His drawings are triumphant descriptions of the, sometimes major, discrepancies between dogs and humans, showing superb drawing ability. Many later anatomists challenged Galen in their texts, though Galen reigned supreme for another century.
A succession of researchers proceeded to refine the body of anatomical knowledge, giving their names to a number of anatomical structures along the way. The 16th and 17th centuries also witnessed significant advances in the understanding of the circulatory system, as the purpose of valves in veins was identified, the left-to-right ventricle flow of blood through the circulatory system was described, and the hepatic veins were identified as a separate portion of the circulatory system. The lymphatic system was also identified as a separate system at this time.
2. 17th and 18th centuries
The study of anatomy flourished in the 17th and 18th centuries. The advent of the printing press facilitated the exchange of ideas. Because the study of anatomy concerned observation and drawings, the popularity of the anatomist was equal to the quality of his drawing talents, and one need not be an expert in Latin to take part.
Many famous artists studied anatomy, attended dissections, and published drawings for money, from Michelangelo to Rembrandt. For the first time, prominent universities could teach something about anatomy through drawings, rather than relying on knowledge of Latin. Contrary to popular belief,the church neither objected to nor obstructed anatomical research despite its antagonism towards other scientific practices.
The increase in demand for cadavers, though, led to rumors about anatomy murder.
Only certified anatomists were allowed to perform dissections, and sometimes then only yearly. These dissections were sponsored by the city councilors and often charged an admission fee, rather like a circus act for scholars. Many European cities, such as Amsterdam, London, Copenhagen, Padua, and Paris, all had Royal anatomists (or some such office) tied to local government. Indeed, Nicolaes Tulp was Mayor of Amsterdam for three terms. Though it was a risky business to perform dissections, and unpredictable depending on the availability of fresh bodies, attending dissections was perfectly legal. Many anatomy students traveled around Europe from dissection to dissection during the course of their study - they had to go where a fresh body was available (e.g. after a hanging) because before refrigeration, a body would decay rapidly and become unsuitable for examination.
Many Europeans interested in the study of anatomy traveled to Italy, then the center of anatomy. Only in Italy could certain important research methods be used, such as dissections on women. M. R. Columbus and Gabriele Falloppio were pupils of Vesalius, the 16th century anatomist. Columbus, as his immediate successor in Padua, and afterwards professor at Rome, distinguished himself by rectifying and improving the anatomy of the bones, by giving correct accounts of the shape and cavities of the heart, of the pulmonary artery and aorta and their valves, and tracing the course of the blood from the right to the left side of the heart, by a good description of the brain and its vessels, and by correct understanding of the internal ear, and the first good account of the ventricles of the larynx. Osteology at nearly the same time found an assiduous cultivator in Giovanni Filippo Ingrassias.
3. 19th century anatomy
During the 19th century, anatomists largely finalised and systematised the descriptive human anatomy of the previous century. The discipline also progressed to establish growing sources of knowledge in histology and developmental biology, not only of humans but also of animals. Extensive research was conducted in more areas of anatomy.
Great Britain was particularly important in this research. Demand for cadavers grew so great there that body-snatching and even anatomy murder came into use as a means of obtaining them. In response, the English Parliament passed the Anatomy Act 1832, which finally provided for an adequate and legitimate supply of corpses by allowing dissection of destitutes. The relaxed restrictions on dissection provided a suitable environment for Gray's Anatomy, a text that was a collective effort and became widely popular. Now seen as unwieldy, Gray's Anatomy was born out of a need to create a single volume on anatomy for the traveling doctor.
The shift from the largely public displays of dissection in anatomy theatres to dissections carried out in classrooms meant that there was a drastic change in who could observe a dissection. Females for example, who at this time were not allowed to attend medical school, could broaden their knowledge by attending the anatomy theatres. So the shift from prosection to dissection meant a reduction in the number of people that could benefit from a single cadaver.
At this point as well tighter regulation of the medical profession and donations of bodies resulted in various implications for carrying out dissections. Private medical schools which offered summer schools and various other courses involving cadaveric dissection allowed one route into gaining membership to the Royal College of Surgeons. However from 1822 the Royal College of surgeons would no longer accept these qualifications, this as result would see these largely unregulated schools begin to close. Not only as a result of this, but the Anatomy Act 1832 made it much harder (more bureaucracy) to obtain bodies for dissection.
The act resulted in only the large teaching hospitals feasibly being able to continue teaching anatomy courses due to agreements with patients that if they donated their body they would receive free treatment. So towards the end of 19th century anatomy courses had been largely professionalised at established medical schools and public dissection was no longer common place.
Another source of anatomy teaching began with the foundation of many medical schools (particularly within the provincial medical schools) and the medical museums found within them. A large portion of training occurred within these up until and for some time after the Second World War. The medical museum was very important and a lot of effort was put into creating something impressive. This was particularly so in provincial medical schools which were just being established that needed credibility not only from other medical schools (namely Oxford and the London teaching hospitals) but also from the public. The museums were not only for students but also members of the public paid to see the exhibits within the museum. This brought not only much needed income but prestige as well. The more exhibits within the museum the more established the medical school appeared to be (at least to the public).
Significant amounts of teaching occurred in the museum as well with students claiming they learnt far more in the museum than they ever did in the lecture theatre. The decline of the museums within medical schools was largely due to the demand in floor space for teaching and new disciplines and less importantly the great improvements in photography and colour texts. For example the museum at Birmingham Medical School is now a computer cluster and teaching rooms, the only remains of the museum are the preserved specimens decorating the walls around the computer cluster.
Modern anatomyAnatomical research in the past hundred years has taken advantage of technological developments and growing understanding of sciences such as evolutionary and molecular biology to create a thorough understanding of the body's organs and structures.
Disciplines such as endocrinology have explained the purpose of glands that anatomists previously could not explain; medical devices such as MRI machines and CAT scanners have enabled researchers to study the organs of living people or of dead ones. Progress today in anatomy is centered in the development, evolution, and function of anatomical features, as the macroscopic aspects of human anatomy have been largely catalogued. The subfield of non-human anatomy is particularly active as modern anatomists seek to understand basic organizing principles of anatomy through the use of advanced techniques ranging from finite element analysis to molecular biology.
With increasing demands on the healthcare system and what could be deemed chronic under-training of doctors (numbers of doctors per capita compared to other industrialised countries) during the latter half of the 20th century, medical schools are now facing massive pressure to train as many doctors as possible. This has meant in recent years cohort sizes have doubled and more in size, in order to try and meet the demand. This has resulted in increased pressure of the facilities at all medical schools in the country.
Anatomy is one department in particular that has had to evolve to accommodate the number of students. At Birmingham dissection was once essential to the teaching of anatomy but since the end of the 1980s the medical school has adopted prosection over dissection. At the time new directives from the General Medical Council (GMC) on the direction medical education was the major factor according the current head of anatomy.
There are also many other reasons why prosection maybe favoured (discussed below). It has probably now become near impossible to restart dissection at Birmingham even if one wanted to. This is due to the fact that current prosection uses a very similar number of cadavers as dissection previously did. If dissection was to be brought back the number of cadavers would be very large due the current cohort size. To increase provision of prosection the medical school is currently investing in the region of £800,000-900,000 on a new prosectorium. This will allow up to about 40 students to observe prosected material in any one session. The vast amount of money required just to increase the amount of prosection demonstrates that it is no longer possible to carry out dissection at Birmingham (and is the case for many other universities).
Prosection makes more efficient use of a cadaver when compared to dissection. A single cadaver when dissecting would be used by up to 5 students whereas prosection allows if necessary and entire cohort to observe the prosected cadaver. Prosection also allows students to observe more than one cadaver whereas in dissection you would tend to just use a single one. Logistically prosection allows more flexibility than dissection as there is no commitment to provide a cadaver per a certain number of students, this in fact create opportunities for cadavers to be used, for example at Birmingham, for Special Study Modules (SSMs) and postgraduate teaching.
Also there are many more aids to teaching anatomy then merely the prosectorium; improvements over the last century in colour images and photographs means that an anatomy text is no longer an aid to dissection but rather a central material to learn from. Plastic models are also regularly used in anatomy teaching sessions and they offer a good substitute to the real thing. One argument against plastic models is that they may provide a false sense of conformity in the human body; there is no doubt quite a difference between a plastic model and a prosected cadaver. Use of living models for anatomy demonstration is once again becoming popular within teaching of anatomy. Anatomy is dynamic, for example the anatomy of the musculoskeletal system is by definition the anatomy of movement.
So to provide an example of this to the audience (students) and be able to demonstrate the possible movements is beneficial. Surface landmarks that can be palpated on another individual also provide practice for future clinical situations. It is possible to do this on oneself and a good example of this being implemented is Integrated Biology at the University of Berkeley; students are encouraged to “introspect” on themselves and link what they are being taught to their own body. This may seem like a relatively obvious idea but to formally link it into teaching of anatomy should aid memory recall.
Donations of bodies have also declined in recent years with a marked decline of public confidence in the medical profession. With scandals such as Alder hay and Bristol, people are less confident that their wishes on what will happen to their body will be carried out, so instead have not donated to medical science when in the past they may have.
The resultant legislation from these scandals (namely the Human Tissue Act 2004) has tightened up the availability of resources to anatomy departments. Another factor facing body donations is the problems arising from the outbreaks of Bovine Spongiform Encephalitis (BSE) in the late 80s and early 90s and the restrictions of handling of brain tissue that resulted from this.
The exact pathology of the human form, variant Creutzfeldt–Jakob disease (vCJD) has meant that patients donating their body who suffered from Alzheimer’s or dementia and of course vCJD means their brains cannot be handled. As the method of transmission of these diseases and the link between them (i.e. is Alzheimer’s vCJD and vice versa) is not fully understood these precautions have to be taken.
Very symptomatic patients are also not normally accepted for cadavers. However this means that students are more limited on what they can dissect within the head, this is particularly a problem in medical schools where dissection is still carried out. It is less of a problem where prosection is carried out as the specimen will have already been dissected.
Conclusion:
Anatomy teaching has changed considerably over the last 1000 years though it is still very much at the heart of the philosophy of western medicine. Western medicine seeks to find a cause to all disease and attempt to cure it; very much cause and effect.
Without a good understanding of the arrangement of the human body then this becomes somewhat challenging. Western medicine is in fact taking a more holistic approach today, with the psychosocial biomedical model of disease. However most practicing doctors if it was proven that there was a biological cause to all the various idiopathic diseases then they would readily adapt their thoughts and treatments accordingly. Anatomy is often regarded as being little left to discover, in that we know what and where most of the body is and does, but there is still many mysteries left to work out. Public awareness of anatomy cannot be detrimental if it sparks interest in the discipline.
The recent controversies with Gunther von Hagens and public displays of dissection may divide opinions on what is ethical even the legality of a public dissection but this surely at least gets people thinking about how doctors learn anatomy and why in some it inspires them to pursue a career. The future of dissection may be uncertain and indeed if pressure on cadavers continues even the few medical schools that continue to do dissection may have to halt. This hopefully however will not reduce the number of people able to benefit from a single cadaver if current prosection methods become the prevalent method of demonstrating gross anatomy.
Branches of anatomy
1. Gross anatomy:Gross anatomy is the study of anatomy at the macroscopic level. The term gross distinguishes it from other areas of anatomical study, including microscopic anatomy, which must be studied with the aid of a microscope.
Techniques of study
Gross anatomy is studied using both invasive and noninvasive methods with the goal of obtaining information about the macroscopic structure and organization of organs and organ systems.
Among the most common methods of study is dissection, in which the body of an animal is surgically opened and its organs studied.
Endoscopy, in which a video camera-equipped instrument is inserted through a small incision in the subject, may be used to explore the internal organs and other structures of living animals. The anatomy of the circulatory system in a living animal may be studied noninvasively via angiography, a technique in which blood vessels are visualized after being injected with an opaque dye.
Other techniques of study include X-ray and MRI.
Many types of multimedia exist for the study of gross anatomy, including textbooks and educational CDs and DVDs.
In education
Most doctoral health profession schools, such as medical and dental schools, require that students complete a course in gross human anatomy. Such courses aim to educate students in basic human anatomy and seek to establish anatomical landmarks that may later be used to aid medical diagnosis. Many schools provide students with cadavers for investigation by dissection, aided by dissectors such as Grant's Dissector, as well as cadaveric atlases (e.g. Rohen's).
Approaches to Studying Gross Anatomy
There are 3 main approaches to studying gross anatomy:
a. Regional and Surface anatomy:
- Regional anatomy or topography anatomy is the method of studying the body's structure by focusing attention on a specific part (e.g., the head), region (the face), or subregion (the nose); examining the arrangement and relationships of the various systemic structures (muscles, nerves, arteries, etc) within it; and then usually continuing to study adjacent regions in an ordered sequence.
- Surface anatomy is an essential part of the study of regional anatomy. Regional anatomy also recognizes the body's organization by layers: skin, subcutaneous tissue, and deep fascia covering the deeper structures of muscles, skeleton, and cavities, which contain viscera (internal organs). Many of these deeper structures are partially evident beneath the body's outer covering and may be studied and examined in living individuals via surface anatomy. Surface anatomy requires a thorough understanding of the anatomy of the structures beneath the surface. In people with stab wounds, for example, a physician must be able to visualize the deep structures that might be injured.
b. Systemic anatomy:
Systemic anatomy is a sequential study of the functional systems of the body. It is recognizes the organization of the body's organs into systems or collective apparatuses that work together to carry out complex functions. The basic systems and the field of study or treatment of each (in parentheses) are:
- Dermatology: The study of the integumentary system. Consists of the skin and its appendages-hair, nails and sweat glands.
- Osteology: The study of the skeletal system. Consists of bones and cartilage.
- Syndesmology: The study of ligaments.
- Myology: The study of the muscular system.
- Angiology: The study of the circulatory system. Consists of Cardiology (The Cardiovascular system-consists of the heart and blood vessels) and the Lymphatic system (a network of lymphatic vessels).
- Neurology: The study of the nervous system. Consists of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves and ganglia, together with their motor and sensory endings).
- Splanchnology: A branch of anatomy concerned with the viscera (internal organs). Consists of Gastroenterology (the study of the digestive or alimentary system-consists of the organs and glands associated with ingestion, mastication/ chewing, deglutition/ swallowing, digestion, and absorption of food and the elimination of feces), Pulmonology (the study of the respiratory system-consists of the air passages and lungs, diaphragm and larynx), Urology (the study of the urinary system-consists of the kidneys, ureters, urinary bladder and urethra), Gynecology (the study of the female's reproductive or genital system), Andrology (the study of the male's reproductive or genital system), and Endocrinology (the study of the endocrine/ hormones system).
c. Clinical anatomy:
- Clinical anatomy or Applied anatomy emphasizes aspects of bodily structure and function important in the practice of medicine, dentistry, and the allied health sciences. It incorporates the regional and systemic anatomy and stresses clinical application.
2. Microscopic anatomy:Known among medical students simply as "micro", microscopic anatomy is the study of the form of normal structures seen under the microscope, as opposed to gross anatomy which involves structures that are big enough to be observed with the naked eye.
Microscopic anatomy means sitting looking at slides, slides, and more slides under the microscope. Microscopic anatomy consists of Cytology and Histology.
a. Cytology means "the study of cells". Cytology is that branch of life science, which deals with the study of cells in terms of structure, function and chemistry.
Based on usage it can refer to:
- Cytopathology: the study of cellular disease and the use of cellular changes for the diagnosis of disease.
- Cell biology: the study of (normal) cellular anatomy, function and chemistry.
b. Histology is the study of the microscopic anatomy of cells and tissues. It is performed by examining a thin slice (section) of tissue under a light microscope or electron microscope. The ability to visualize or differentially identify microscopic structures is frequently enhanced through the use of histological stains. Histology is an essential tool of biology and medicine.
Histopathology, the microscopic study of diseased tissue, is an important tool in anatomical pathology, since accurate diagnosis of cancer and other diseases usually requires histopathological examination of samples. Trained medical doctors, frequently board-certified as pathologists, are the personnel who perform histopathological examination and provide diagnostic information based on their observations.
The trained scientists who perform the preparation of histological sections are histotechnicians, histology technicians (HT), histology technologists (HTL), medical scientists, medical laboratory technicians, or biomedical scientists. Their field of study is called histotechnology.
3. Developmental anatomy:Developmental anatomy is the branch of anatomy that studies structural changes of an individual from fertilization to maturity. Developmental anatomy is also called Embryology.
4. Comparative anatomy:Comparative anatomy is the study of similarities and differences in the anatomy of organisms. It is closely related to evolutionary biology and phylogeny (the evolution of species).
Two major concepts of comparative anatomy are:
a. Homologous structures - structures (body parts/anatomy) which are similar in different species because the species have common descent. They may or may not perform the same function. An example is the forelimb structure shared by cats and whales.
b. Analogous structures - structures which are similar in different organisms because they evolved in a similar environment, rather than were inherited from a recent common ancestor. They usually serve the same or similar purposes. An example is the torpedo body shape of porpoises and sharks. It evolved in a water environment, but the animals have different ancestors.
The rules for development of special characteristics which differ significantly from general homology were listed by Karl Ernst von Baer (the Baer laws).
Anatomical position
As a standard point or frame of reference, the human body is described as being in the anatomical position when it is standing erect, head, gaze (eyes), toes directed anteriorly (forward), arms adjacent to the sides with the palms facing anteriorly, lower limbs close together with the feet together flat on the floor.
Anatomical planes
To study anatomy, we will spend time studying not only the surface anatomy of many organs, but we will also have to look at the interior anatomy of many organs. For example, the brain has a lot of interesting internal anatomy. In order to see these internal structures we will have to cut, or section, the various organs or parts of the body. Now three dimensionally there would have to be three different directions, or planes, that we can cut something.
Tranverse plane:
The first direction, or sectional plane, that we may use to cut a specimen could be to cut it in a horizontal plane. This type of cut would leave you with a top piece and a bottom piece. This type of section is called a transverse section or plane.
Vertical plane:
A different type of cut would be to cut, or section, a specimen in a vertical direction so that you are left with a front piece and a back piece. This type of section is called a coronal section or plane. For example, if you wanted to look at the interior structures of the brain and how their shapes vary as you move from front to back inside the brain, you would need to make a series of coronal sections to follow the changes in the shape of the internal structures.
Median plane:
The third direction that you may wish to cut a specimen, or the entire body, is to cut it into a right piece and a left piece. This type of section is also called as a sagittal section or plane. Now be careful, sagittal section does not always have to be right down the middle. To cut a specimen right down the middle producing equal right and left halves is called a midsagittal section. To section a secimen into right and left pieces that are not necessarily equal (on off-center cut in the sagittal plane) is to make a parasagittal section.
*Remember, we are cutting up a organ or part of the body in order to better visualize the internal structures of that organ or area of the body. You will have to then use your imagination to visualize in your mind how it looks uncut.
Terms of Relationship and Comparison
Superficial, intermediate, and deep describe the position of structures relative to the surface of the body or the relationship of one structure to another underlying or overlying structure.
- Superficial: Closer to the surface
- Intermediate: Between a superficial and a deep structure
- Deep: Farther down below the surface
Medial and lateral
- Medial: Nearer the midline of the body or a structure
- Lateral: Farther away from the midline of the body or a structure
External and internal mean farther from and nearer to the center of an organ or cavity, respectively, regardless of direction.
- External: Farther from to the center of an organ or cavity, respectively, regardless of direction.
- Internal: Nearer to the center of an organ or cavity, respectively, regardless of direction.
Posterior (dorsal), anterior (ventral), and rostral
- Anterior (Ventral): At the fronts
- Rostral: Often used instead of anterior when decribing parts of the brain; it mean toward the rostrum (L. from beak); however, in humans it denotes nearer the anteriorpart of the head (e.g., the frontal lobe of the brain is rostral to the cerebellum)
- Posterior (Dorsal): At the back
Inferior, Caudal, Superior, and Cranial
- Superior: Structure that is nearer the vertex, the top-most point of the cranium
- Cranial (Cephalic): Toward the head
- Inferior: Structure that is situated nearer the sole of the foot
- Caudal: Toward the tail (coccyx)
Proximal and distal are used when contrasting positions nearer to or farther from the attachment of a limb or the central aspect of a linear structure, respectively.
- Proximal: Closer to a structure
- Distal: Further away from a structure
Dorsum, Palm (hand), and Sole (foot)
- Dorsum: Usually refers to the superior or posterior (back) surface of any part that protrudes anteriorly from the body, such as the dorsum of the tongue, nose, penis, or foot. It is also used to describe the back of the hand.
- Palm: The flat of the hand, exclusive of the thumb and other fingers, and is the opposite of the dorsum of the hand.
- Sole: The inferior aspect or bottom of the foot, much of which is in contact with the ground when standing barefoot.
Terms of Laterally
Bilateral and unilateral
- Bilateral: Paired structures having right and left members (e.g., the kidneys)
- Unilateral: Single structure (one side only)-e.g. spleen
Ipsilateral and Contralateral
- Ipsilateral: On the same side of the body or structure
- Contralateral: On the opposite side of the body or structure
Terms of Movement
Flexion, Dorsiflexion, and Plantarflexion
- Flexion: Bending or decreasing the angle between the bones or parts of the body
- Dorsiflexion: Flexion at the ankle joint (e.g., when walking uphill or lifting the toes off the ground)
- Plantarflexion: Turns the foot or toes toward the plantar surface (e.g., when standing on your toes)
Extension, and Hyperextension (overextension)
- Extension: Straightening or increasing the angle between the bones or parts of the body
- Hyperextension: Extension of a limb or part beyond the normal limit. Hyperextension can cause injury, such as "whiplash" (i.e., hyperextension of the neck during a rear-end automobile collision)
Abduction, Abduction of the digits (fingers or toes), Abduction of the neck and trunk, Adduction, and Adduction of the digits (fingers or toes)
- Abduction: Moving away from the median plane in the frontal plane (e.g., when moving an upper limb away from the side of the body)
- Abduction of the digits: Spreading them apart-moving the other fingers away from the naturally positioned 3rd (middle) finger or moving the other toes away from the naturally positioned 2nd toe. The 3rd finger and 2nd toe medially or laterally abduct away from the neutral position.
- Abduction of the neck and trunk: Special forms of abduction for only the neck and trunk. The face and upper trunk are directed anteriorly as the head and/or shoulders tilt to the right or left side, causing the midline of the body itself to become bent sideways. This is a compound movement occuring between many adjacent vertebrae.
- Adduction: Moving toward the median plane in a frontal plane (e.g., when moving an upper limb toward the side of the body)
- Adduction of the digits: Reapproximating the spread fingers or toes or moving the other digits toward the neutral position of the 3rd finger or 2nd toe. The medially or laterally abducted 3rd finger or 2nd toe adducts back to the neutral position. The thumb is rotated 90 degree relative to the other digits. Therefore, the thumb flexes and extends in the frontal plane, and abducts and adducts in the sagittal plane
Circumduction, and Rotation (medial/internal rotation & lateral/external rotation)
- Circumduction: A circular movement that is a combination of flexion, extension, abduction, and adduction occurring in such a way that the distal end of the part moves in a circle. Circumduction can occur at any joint at which all the above-mentioned movements are possible (e.g., the hip joint)
- Rotation: Turning or revolving a part of the body around its longitudinal axis, such as turning one's head to face sideways. Medial rotation brings the anterior surface of a limb closer to the median plane. Lateral rotation takes the anterior surface away from the median plane
Pronation, and Supination
- Supine: Lying face up
- Prone: Lying face down
Opposition, and Reposition
- Opposition: The movement by which the pad of the 1st digit (thumb) is brought to another digit pad. This movement is used to pinch, button a shirt, and lift a teacup by the handle
- Reposition: The movement of the 1st digit from the position of opposition back to its anatomical position
Protrusion, and Retrusion
- Protrusion: A movement anteriorly (forward) as in protruding the mandible (chin), lips, or tongue
- Retrusion: A movement posteriorly (backward) as in retruding the mandible (chin), lips, or tongue
Protraction, and Retraction
- Protraction: Use most commonly for anterior movements of the shoulder
- Refraction: Use most commonly for posterior movements of the shoulder
Elevation, and Depression
- Elevation: Raises or moves a part superior
- Depression: Lowers or moves a part inferiorly
Eversion, and Inversion
- Eversion: Moves the sole of the foot away from the median plane (turning the sole laterally). When the foot is fully everted it is also dorsiflexed
- Inversion: Moves the sole of the foot toward the median plane (facing the sole medially). When the foot is fully inverted it is also plantarflexed
Regional Terms in Anatomy
- Cephalic: Located on, in, or near the head.
- Vertebral: Located on, in, or near the vertebra (back bones).
- Thoracic: Located on, in, or near the chest.
- Appendicular: Relating to, or consisting of an appendage or appendages, especially the limbs.
- Brachial: Relating to, or resembling the arm or a similar or homologous part, such as the foreleg, wing, or other forelimb of a vertebrate.
- Lumbar: Near, or relating to the part of the body between the lowest ribs and the hipbones.
The body cavities
Body cavity divided into 4 cavities:
1. Dorsal cavity subdivided into cranial cavity (contains brain) and vertebral cavity (contains spinal cord).
2. Ventral cavity subdivided into thoracic cavity, and abdominopelvic cavity.
a.Thoracic cavity (contains heart and lungs) consists of 4 cavities:
- Superior mediastinum cavity
- Lungs and pleural cavity (left and right cavities)
- Mediastinum, with heart and pericardial cavity
b. Abdominopelvic cavity consists of 2 cavities:
- Abdominal cavity: Contains digestive viscera, kidneys, and peritonial cavity
- Pelvic cavity: Contains bladder, reproductive organs, rectum, and peritoneal cavity
3. Serous cavity: A narrow cavity lined by serous membrane and consists of:
- Parietal serous: forming the outer wall cavitas
- Visceral serous: covering the visceral organs
4. The other small cavities: In the head, and between the joints.
The serous membranes
How to place organs into these cavities and have them stay in place? Even trickier, how to place an organ that is always moving, such as the heart or the lungs or even intestines, into one of these hollow cavities and keep it in place without firmly attaching it to the inside walls of the cavity since the organ needs to be able to move freely?
Let's start with the heart as an example. Imagine a closed fist as the heart. As the 'fist/heart' push up against the balloon, one side of the balloon is in direct contact with the 'fist/heart' while the opposite side of the balloon is not touching the 'fist/heart'. As the 'fist/heart' continue to push into the balloon, by 'fist/heart' will become completely surrounded by the balloon.
Yet the other side of the balloon is not touching the 'fist/heart', but is separated from it by the air in the balloon. Assume that the balloon is stick on the outside so that when the 'fist/heart' push up against it farther and farther, the balloon sticks to the 'fist/heart'. If the other side of the balloon held with other hand, the 'fist/heart' will not fall to the ground since it is stuck to the sticky surface of the balloon (remember, the 'fist/heart' is not suppost to be attached at the wrist).
So the heart is free to beat and move, yet it won't fall down or wiggle loose since the other side of the balloon is attached to the insides of the ribs. Why this works so well is that it is just one single balloon. But one single balloon with two surfaces. One surface attached to the 'fist/heart' and the other surface attached to the insides of the ribs. This balloon is called the pericardium.
Instead of the balloon being filled with air, it is filled with fluid, the pericardial fluid. Now the pericaridium can be named according to what surface you are talking about, the surface stuck to the heart or the surface stuck to the insides of the ribs. This is anatomy, so we give a name to each surface of the pericardium.
The part of the pericardium that is stuck to the heart itself is called the visceral pericaridum while the other surface of the pericardium that is attached to the insides of the ribs is called the parietal pericardium. The pericardium has both the visceral portion and the parietal portion, but it is still one continuous balloon, one continuous membrane called the pericardium.
Abdominal Regions
Anatomy and Clinical physical examinations
Physical examination or clinical examination is the process by which a doctor investigates the body of a patient for signs of disease. It generally follows the taking of the medical history — an account of the symptoms as experienced by the patient. Together with the medical history, the physical examination aids in determining the correct diagnosis and devising the treatment plan. This data then becomes part of the medical record.
Format and interpretation
Although providers have varying approaches as to the sequence of body parts, a systematic examination generally starts at the head and finishes at the extremities.
After the main organ systems have been investigated by inspection, palpation, percussion and auscultation, specific tests may follow (such as a neurological investigation, orthopedic examination) or specific tests when a particular disease is suspected (e.g. eliciting Trousseau's sign in hypocalcemia).
With the clues obtained during the history and physical examination the healthcare provider can now formulate a differential diagnosis, a list of potential causes of the symptoms. Specific diagnostic tests (or occasionally empirical therapy) generally confirm the cause, or shed light on other, previously overlooked, causes.
While the format of examination as listed below is largely as taught and expected of students, a specialist will focus on their particular field and the nature of the problem described by the patient. Hence a cardiologist will not in routine practice undertake neurological parts of the examination other than noting that the patient is able to use all four limbs on entering the consultation room and during the consultation become aware of their hearing, eyesight and speech. Likewise an Orthopaedic surgeon will examine the affected joint, but may only briefly check the heart sounds and chest to ensure that there is not likely to be any contraindication to surgery raised by the anaesthetist. Non-specialists generally examine the genitals only upon request of the patient.
A complete physical examination includes evaluation of general patient appearance and specific organ systems. It is recorded in the medical record in a standard layout which facilitates others later reading the notes. In practice the vital signs of temperature examination, pulse and blood pressure are usually measured first.
