- Email: [email protected]
Clean and easy anatomy
DISSECTING ROOM
Telegony n 1820, the Earl of Morton, FRS, communicated to the Royal Society of London, UK, a “singular fact”. In attempting to domesticate the quagga—a zebra-like, South American member of the horse family (now extinct)—he was forced to breed a male with a female Arabian mare. The resulting hybrid was predictable, but the singularity appeared when the Arabian mare was subsequently mated with an Arabian stallion: their offspring possessed colour and hair characteristics of the quagga. Animal breeders had long worried that prized pure-bred females— whether of horses, pigs, sheep, or dogs—would be forever contaminated were they allowed to copulate with a male of impure blood. The first impregnation had lasting consequences, since the fetus “inoculated” the mother’s blood and through it her whole being with characteristics of its sire. This doctrine carried scientific respectability throughout the 19th
I
century: Claude Bernard, Charles Darwin, and many other shrewd observers accepted the observational evidence and elaborated theories to account for it. They called it “infection of the germ”, a neat instance of a modern sounding phrase with an obsolete meaning: the fetus permanently affecting the mother’s reserve eggs. This idea was given its impressive Greek name, telegony (“at a distance” and “offspring”) by August Weismann (1834–1914), the German biologist whose rigorous separation of somatic and germinal cells cast doubt on the inheritance of acquired characteristics. Weismann believed his notion of the germ plasm could explain telegony, should it be shown to exist, but he doubted its reality. Although always largely an animal breeders’ issue, telegony was also invoked in ideas about human inheritance. Imperialists found it a convenient explanation of the decimation of aboriginal groups after contact with Europeans, the assumption being that
Clean and easy anatomy Primal 3D Interactive Series: Hand, Shoulder, Knee 1.1, Hip, Foot and Ankle London: Primal Pictures, 2001. 6 CD-ROMs. £470. ISBN 1902470672. t seems too good to be true— layer from superficial to deep, and the perfect solution to the eternal back again. Each regional illustration problems of smelly cadavers, ressurgoes from bony details to the skin, rectionists, formalin allergies, clumsy dissecting partners, and the skimpy teaching of anatomy in medical school. The musculoskeletal system is finally exposed here, in one convenient six CD-ROM set. The publishers have plans for further CD-ROMs on surface anatomy of the head and neck, the thoracic and abdominal contents, and total hip replacements. The real test of this format—a disk on the central nervous system—is still, unfortunately, several years down the line. Even so, the Primal 3D Interactive Series on the hand, shoulder, knee, hip, foot, and ankle is a good sample. Rotating bits of anatomy can be stripped layer by simplified Layer of the inguinal region
I
1256
their women became less fertile after cohabitation with white men. The offspring of widows in second marriages were often believed to favour the woman’s deceased husband. Emile Zola used the theory as a theme in his novel Madeleine Férat (1868). Experiments by Weismann and the Scottish naturalist J C Ewart cast doubt on the accuracy of the animal observations. The statistician Karl Pearson pointed out that, were telegony true, the later children of the same couple ought increasingly to resemble the father, which he showed was not the case. With the triumph of theories of hard heredity, telegony disappeared. It had not all been doom and gloom, however. Within popular culture, the doctrine offered women a bit of freedom in marriage, since adulterous offspring were believed to resemble the legal father more than the biological one. Hence the proverb: “filium ex adultera excusare matrem a culpa”. Bill Bynum Wellcome Trust Centre for the History of Medicine at UCL, 24 Eversholt Street, London NW1 1AD, UK e-mail: [email protected]
which is marked conveniently with the dermatomes, and descends again into the nerves and vessels. There is a handy correlation with magnetic resonance imaging (MRI) at the appropriate level—impressively supplied in tranverse, coronal, and sagittal sections. The sawn, frozen sections from The National Library of Medicine’s Visible Human Project are also included, and it makes quite a neat movie to start at the toes and watch each part pile up, slice by fascinating slice. There are film sequences of a live male body to outline single muscles in complex movements. There is a great exploding carpus on the hand disk. Those pesky little bones take off like asteroids and rotate nicely, showing all their hidden surfaces and compound curves. Two capitates dance in mirror image of each other— these images could, perhaps, be used as a screen saver and the shapes would eventually sink in. However, two things temper one’s enthusiasm for such an excellent product: design flaws Primal Pictures
Discarded diagnoses
THE LANCET • Vol 359 • April 6 2002 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.
DISSECTING ROOM
and misleading text. It should be possible to magnify the windows, or at least illuminate the background. The layout is adequate for such welldefined things as muscle origins on bare bones, but add layers, and the detail becomes distinctly murky. On most still screens, there are blue and green squares in the right hand corner that are joined by an arrow, which means MRI can be used to match the diagram, or vice-versa. The MRI forward button will make the diagram track, but the contrary is not true. The “layer scroller” on the model of the sagittal ankle just takes away slices, not layers. On the lumbar spine screen, there are kidneys on the MRI image, but because you are not able to obtain a superficial view on the coronal sections, you do not end up with the corresponding MRI slice. On the spine disc, autorotate only means swivel, although if you then look at the coronal and sagittal models you do get the whole picture, albeit in pieces. There are useful multiple choice tests in each section, but these are marred by indistinct red cross-hatches that are
meant to highlight the relevant piece of anatomy. No-one apparently reviewed or cross-read the clinical and radiology text, which is repeated at embarrassing length, especially in the description of the Achilles’ tendon. This oversimplified section is full of typographical errors and strange formatting. The section on clinical pathology is even weaker, and illustrated by unclear MRI slides. Multiple clicks are needed to see these slides properly, and you never know whether you are going to see the live male body, or a blue glove plucking at tendons in a darkened room, which is a little disconcerting. If you are curious about the “concept of ulnar variance”, click on the link, and a power point slide crops up with two bullet points. The text is more useful when it simply describes what is shown. I could not see the point of describing ossification centres, if they are not illustrated—an embryogenesis CD-ROM is needed to do that subject justice. An unsuccessful attempt has been made to join line
drawings to cadavers by red text that links to dissection photographs of the region in question; structures cannot be selected by the mouse with the same accuracy. On the knee CD-ROM there are great film sequences of the anterior and posterior cruciate ligaments in flexion, and watching these ligaments slide across the idealised surface of a medial condylar notch makes one wince for all the arthritic catches that age puts there in time. A sequence showing the screw home motion of the patellar during knee flexion is a masterpiece of simplicity and probably the most useful tool for patients’ education in this set. These CD-ROMs essentially replace, at considerable expense, the acetate sheets that used to make up multilayered anatomical illustrations. The designers might want to give some thought to the nostalgia they thereby induce for a big heavy book with real pages and accurate content. Laragh Gollogly The Lancet, London, UK
Sorting through the signs Evidence-Based Physical Diagnosis Steven McGee. Philadelphia: W B Saunders, 2001. Pp 910. $45.95. ISBN 0721686931.
E
vidence-Based Physical Diagnosis attempts to integrate the tradition and history of physical examination with the growing body of evidence about the diagnostic accuracy and reliability of the various physical findings that physicians use to assess patients. Steven McGee, an associate professor of internal medicine with some 20 years’ experience of teaching physical examination skills to medical students, has done an excellent job of integrating these disparate subjects. The first three chapters are devoted to a detailed discussion of probabilities, diagnostic accuracy, and reliability. These initial chapters are beautifully written, and include one of the most readable accounts of likelihood ratios I have encountered. Clinicians, who need simple and practical tools, will appreciate the methods for approximating post-test probability that are outlined in this section. After this introductory section, there are 56 chapters about the physical findings in a particular disease state, for example, in patients with pulmonary embolism or anaemia. Most chapters include tables that list sensitivities, specificities, and likelihood ratios for
each sign and these data are the highlights of the text. For example, table 36.1 shows these features for the third and fourth heart sounds. The tables are kept simple by including only a single number or a range for each value, but a concluding chapter lists confidence intervals for each of the likelihood ratios cited in the text. Similarly, the presentation of the Wells scoring scheme for pretest probability of deep-vein thrombosis (tables 50.2, 50.3) was comprehensive and its role in clinical practice well defined. The organisation of the text can be challenging. McGee has placed the chapter on mental status in the section on general appearance; similarly, the chapters on hearing and pupils are in the head and neck section, rather than in the section on neurological examination. The amount of detail for topics varies widely. There is an in-depth and useful discussion of pupillary reflexes, which explores both the history and the diagnostic algorithm for abnormal findings. By contrast, the sections on protein-energy malnutrition, weight loss, and hypovolaemia are superficial. Some important topics,
THE LANCET • Vol 359 • April 6, 2002 • www.thelancet.com
such as examination of the breast, male genitals, and pelvic area are not addressed at all. Furthermore, some disease states are explored in detail, whereas others receive only cursory treatment—for example, the five indepth cardiology topics are not balanced by any detailed explorations of the abdominal examination. However, this shortcoming may reflect the limited data on certain topics. The detailed chapter on congestive heart failure is excellent, but it would have been useful to have a similar discussion of the findings of physical examination in coronary artery disease (Levine’s sign, earlobe creases, or xanthelasma). This book, with its inclusion in one place of so much data on the reliability of physical findings is a welcome adjunct to the teaching of physical diagnosis to medical students. Evidence-Based Physical Diagnosis would also assist the more experienced clinician in honing their understanding of the usefulness of physical diagnosis findings and manoeuvres. McGee does presuppose a substantial baseline knowledge in the reader and omits discussion of several important body systems, so the book is not for inexperienced practitioners. *Lorne Becker, Sara Jo Grethlein Department of Family Medicine, SUNY Health Science Center at Syracuse, Syracuse, NY 13210, USA
1257
For personal use. Only reproduce with permission from The Lancet Publishing Group.
Telegony n 1820, the Earl of Morton, FRS, communicated to the Royal Society of London, UK, a “singular fact”. In attempting to domesticate the quagga—a zebra-like, South American member of the horse family (now extinct)—he was forced to breed a male with a female Arabian mare. The resulting hybrid was predictable, but the singularity appeared when the Arabian mare was subsequently mated with an Arabian stallion: their offspring possessed colour and hair characteristics of the quagga. Animal breeders had long worried that prized pure-bred females— whether of horses, pigs, sheep, or dogs—would be forever contaminated were they allowed to copulate with a male of impure blood. The first impregnation had lasting consequences, since the fetus “inoculated” the mother’s blood and through it her whole being with characteristics of its sire. This doctrine carried scientific respectability throughout the 19th
I
century: Claude Bernard, Charles Darwin, and many other shrewd observers accepted the observational evidence and elaborated theories to account for it. They called it “infection of the germ”, a neat instance of a modern sounding phrase with an obsolete meaning: the fetus permanently affecting the mother’s reserve eggs. This idea was given its impressive Greek name, telegony (“at a distance” and “offspring”) by August Weismann (1834–1914), the German biologist whose rigorous separation of somatic and germinal cells cast doubt on the inheritance of acquired characteristics. Weismann believed his notion of the germ plasm could explain telegony, should it be shown to exist, but he doubted its reality. Although always largely an animal breeders’ issue, telegony was also invoked in ideas about human inheritance. Imperialists found it a convenient explanation of the decimation of aboriginal groups after contact with Europeans, the assumption being that
Clean and easy anatomy Primal 3D Interactive Series: Hand, Shoulder, Knee 1.1, Hip, Foot and Ankle London: Primal Pictures, 2001. 6 CD-ROMs. £470. ISBN 1902470672. t seems too good to be true— layer from superficial to deep, and the perfect solution to the eternal back again. Each regional illustration problems of smelly cadavers, ressurgoes from bony details to the skin, rectionists, formalin allergies, clumsy dissecting partners, and the skimpy teaching of anatomy in medical school. The musculoskeletal system is finally exposed here, in one convenient six CD-ROM set. The publishers have plans for further CD-ROMs on surface anatomy of the head and neck, the thoracic and abdominal contents, and total hip replacements. The real test of this format—a disk on the central nervous system—is still, unfortunately, several years down the line. Even so, the Primal 3D Interactive Series on the hand, shoulder, knee, hip, foot, and ankle is a good sample. Rotating bits of anatomy can be stripped layer by simplified Layer of the inguinal region
I
1256
their women became less fertile after cohabitation with white men. The offspring of widows in second marriages were often believed to favour the woman’s deceased husband. Emile Zola used the theory as a theme in his novel Madeleine Férat (1868). Experiments by Weismann and the Scottish naturalist J C Ewart cast doubt on the accuracy of the animal observations. The statistician Karl Pearson pointed out that, were telegony true, the later children of the same couple ought increasingly to resemble the father, which he showed was not the case. With the triumph of theories of hard heredity, telegony disappeared. It had not all been doom and gloom, however. Within popular culture, the doctrine offered women a bit of freedom in marriage, since adulterous offspring were believed to resemble the legal father more than the biological one. Hence the proverb: “filium ex adultera excusare matrem a culpa”. Bill Bynum Wellcome Trust Centre for the History of Medicine at UCL, 24 Eversholt Street, London NW1 1AD, UK e-mail: [email protected]
which is marked conveniently with the dermatomes, and descends again into the nerves and vessels. There is a handy correlation with magnetic resonance imaging (MRI) at the appropriate level—impressively supplied in tranverse, coronal, and sagittal sections. The sawn, frozen sections from The National Library of Medicine’s Visible Human Project are also included, and it makes quite a neat movie to start at the toes and watch each part pile up, slice by fascinating slice. There are film sequences of a live male body to outline single muscles in complex movements. There is a great exploding carpus on the hand disk. Those pesky little bones take off like asteroids and rotate nicely, showing all their hidden surfaces and compound curves. Two capitates dance in mirror image of each other— these images could, perhaps, be used as a screen saver and the shapes would eventually sink in. However, two things temper one’s enthusiasm for such an excellent product: design flaws Primal Pictures
Discarded diagnoses
THE LANCET • Vol 359 • April 6 2002 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.
DISSECTING ROOM
and misleading text. It should be possible to magnify the windows, or at least illuminate the background. The layout is adequate for such welldefined things as muscle origins on bare bones, but add layers, and the detail becomes distinctly murky. On most still screens, there are blue and green squares in the right hand corner that are joined by an arrow, which means MRI can be used to match the diagram, or vice-versa. The MRI forward button will make the diagram track, but the contrary is not true. The “layer scroller” on the model of the sagittal ankle just takes away slices, not layers. On the lumbar spine screen, there are kidneys on the MRI image, but because you are not able to obtain a superficial view on the coronal sections, you do not end up with the corresponding MRI slice. On the spine disc, autorotate only means swivel, although if you then look at the coronal and sagittal models you do get the whole picture, albeit in pieces. There are useful multiple choice tests in each section, but these are marred by indistinct red cross-hatches that are
meant to highlight the relevant piece of anatomy. No-one apparently reviewed or cross-read the clinical and radiology text, which is repeated at embarrassing length, especially in the description of the Achilles’ tendon. This oversimplified section is full of typographical errors and strange formatting. The section on clinical pathology is even weaker, and illustrated by unclear MRI slides. Multiple clicks are needed to see these slides properly, and you never know whether you are going to see the live male body, or a blue glove plucking at tendons in a darkened room, which is a little disconcerting. If you are curious about the “concept of ulnar variance”, click on the link, and a power point slide crops up with two bullet points. The text is more useful when it simply describes what is shown. I could not see the point of describing ossification centres, if they are not illustrated—an embryogenesis CD-ROM is needed to do that subject justice. An unsuccessful attempt has been made to join line
drawings to cadavers by red text that links to dissection photographs of the region in question; structures cannot be selected by the mouse with the same accuracy. On the knee CD-ROM there are great film sequences of the anterior and posterior cruciate ligaments in flexion, and watching these ligaments slide across the idealised surface of a medial condylar notch makes one wince for all the arthritic catches that age puts there in time. A sequence showing the screw home motion of the patellar during knee flexion is a masterpiece of simplicity and probably the most useful tool for patients’ education in this set. These CD-ROMs essentially replace, at considerable expense, the acetate sheets that used to make up multilayered anatomical illustrations. The designers might want to give some thought to the nostalgia they thereby induce for a big heavy book with real pages and accurate content. Laragh Gollogly The Lancet, London, UK
Sorting through the signs Evidence-Based Physical Diagnosis Steven McGee. Philadelphia: W B Saunders, 2001. Pp 910. $45.95. ISBN 0721686931.
E
vidence-Based Physical Diagnosis attempts to integrate the tradition and history of physical examination with the growing body of evidence about the diagnostic accuracy and reliability of the various physical findings that physicians use to assess patients. Steven McGee, an associate professor of internal medicine with some 20 years’ experience of teaching physical examination skills to medical students, has done an excellent job of integrating these disparate subjects. The first three chapters are devoted to a detailed discussion of probabilities, diagnostic accuracy, and reliability. These initial chapters are beautifully written, and include one of the most readable accounts of likelihood ratios I have encountered. Clinicians, who need simple and practical tools, will appreciate the methods for approximating post-test probability that are outlined in this section. After this introductory section, there are 56 chapters about the physical findings in a particular disease state, for example, in patients with pulmonary embolism or anaemia. Most chapters include tables that list sensitivities, specificities, and likelihood ratios for
each sign and these data are the highlights of the text. For example, table 36.1 shows these features for the third and fourth heart sounds. The tables are kept simple by including only a single number or a range for each value, but a concluding chapter lists confidence intervals for each of the likelihood ratios cited in the text. Similarly, the presentation of the Wells scoring scheme for pretest probability of deep-vein thrombosis (tables 50.2, 50.3) was comprehensive and its role in clinical practice well defined. The organisation of the text can be challenging. McGee has placed the chapter on mental status in the section on general appearance; similarly, the chapters on hearing and pupils are in the head and neck section, rather than in the section on neurological examination. The amount of detail for topics varies widely. There is an in-depth and useful discussion of pupillary reflexes, which explores both the history and the diagnostic algorithm for abnormal findings. By contrast, the sections on protein-energy malnutrition, weight loss, and hypovolaemia are superficial. Some important topics,
THE LANCET • Vol 359 • April 6, 2002 • www.thelancet.com
such as examination of the breast, male genitals, and pelvic area are not addressed at all. Furthermore, some disease states are explored in detail, whereas others receive only cursory treatment—for example, the five indepth cardiology topics are not balanced by any detailed explorations of the abdominal examination. However, this shortcoming may reflect the limited data on certain topics. The detailed chapter on congestive heart failure is excellent, but it would have been useful to have a similar discussion of the findings of physical examination in coronary artery disease (Levine’s sign, earlobe creases, or xanthelasma). This book, with its inclusion in one place of so much data on the reliability of physical findings is a welcome adjunct to the teaching of physical diagnosis to medical students. Evidence-Based Physical Diagnosis would also assist the more experienced clinician in honing their understanding of the usefulness of physical diagnosis findings and manoeuvres. McGee does presuppose a substantial baseline knowledge in the reader and omits discussion of several important body systems, so the book is not for inexperienced practitioners. *Lorne Becker, Sara Jo Grethlein Department of Family Medicine, SUNY Health Science Center at Syracuse, Syracuse, NY 13210, USA
1257
For personal use. Only reproduce with permission from The Lancet Publishing Group.