Transverse sections of the elbow region in man made into transparencies and embedded in plastic in a self-study module.код для вставкиСкачать
THE ANATOMICAL RECORD 210:541-547 (19841 Transverse Sections of the Elbow Region in Man, Made Into Transparencies and Embedded in Plastic in a Self-study Module L.M.A. LATASTER, J.W. RENSEMA, H. VAN MAMEREN, AND J. DRUKKER Capacity Group Anatomy/Embrydogy, Faculty of Medicine, National University of Limburg, I? 0. Box 616, 6200 MD Maastricht, The Netherlands ABSTRACT This paper describes a valuable tool for medical teaching. It is a detailed description of a method to present transparent sections embedded in plastic, placed in a self-instruction module by means of a vertical storage system. It includes the use of three-dimensional graphic reconstructions. Other applications are also indicated. The medical school of the National University of Limburg a t Maastricht is recently founded (1975). The curriculum of this school differs in some respects from that of older schools. It puts a heavy emphasis on the self-activity of the students; in other words, the curriculum is student-centered and not docent-centered. A second characteristic of the curriculum is that it is not subject-based but problem-based. This means, among other things, that disciplines do not occur as separate entities in the curriculum, but that the educational offer to students is of multidisciplinary character. The study of medical problems of related nature is clustered into blocks of 6 weeks. For each period a block book is constructed in which the problems are assembled. The docent is to procure the means by which the student can try to achieve the set goals without any emphasis on direct contact between docent and student. The goals derived from each problem during a given block may belong to different disciplinary territories. Moreover, the assessment of increase in knowledge and insight is again a primary task of the student. The teacher has to offer the facilities for self-evaluation. It is mentioned here in parentheses that next to this formative evaluation, there exists a system of summative evaluation. This educational strategy demands a n entirely different attitude from the teacher as compared with the situation in docent-centered, subject-based curricula. It will be clear that especially for gross anatomy, an educational policy as outlined above poses serious difficulties (Drukker et al., 1981).The anatomist has to expose students, or rather give students the oppor0 1984 ALAN R. LISS. INC. tunity to expose themselves, to situations in which they can improve upon their knowledge of anatomy without relying on formal lecturing andor formal labs where the body is systematically dissected or where prosected specimens allow for discipline-oriented studies. Other resources have to be developed therefore. The study of (consecutive) transparent sections offers a unique opportunity to work independently on enhancing one’s insight in the third dimension, given the understanding that the sections are accompanied by adequate explanation. Whereas sections comprise all elements in topographical arrangement, the quality of the accompanying text influences the direction and the level at which they are used. The nature of the multidisciplinary problem can thus define the specific use of the sections in a given case. The sections should be offered to the students in such a way that their setting fulfils at least some of the following characteristics: 1) they should allow for, rather stimulate, docent-independent learning 2) they are to make self-evaluation possible 3) they should be “student-proof’ 4) their construction should not be too time-consuming 5 ) they should have some versatility 6 ) they should consume as little space as possible 7) they should not be too expensive. Apart from this set of educational and constructional criteria it should of course be Received February 13, 1984; accepted June 5, 1984 L.M.A. LATASTER ET AL. 542 \ t’ . \ V Fig. 1. The plastic embedding procedure of the anatomical sections. a) The covering of the embedding. b) The unfinished mounting. A, acrylic embedding con- tainer; 1,2,3, several layers of catalyzed polyester resin; B, anatomical section; C, acrylic covering container; D, line at which the rims of the mounting are sawn off. stated that the learning goals that can be We made use of a method which has been attained with such resources must match the developed to preserve transverse sections. objectives the school has formulated for the They were made transparent by applying phase of the curriculum in which the stu- methylsalicylate (2-hydroxybenzoic acid dents are confronted with a given resource. methyl ester; oil of Wintergreen) according In the following we will describe the design to Spalteholz (Piechocki, 1979).Subsequently and construction of a learning resource which they were embedded in polyester resin (Lafulfils most of the given criteria. This has taster and van Mameren, 1983). been given the appearance of a n educational The plastic embedding is necessary to make module (Pallie and Brain, 1978; Mc. Phee- the transparent sections accessible as a ters, 1979). learning resource because the vapor of methAs a n example the elbow region has been ylsalicylate is harmful to the health. Morechosen. over the latter preserving method is very A METHOD FOR TEACHING GROSS ANATOMY 543 Fig. 2. One slide containing six sections and pulled in front of the display-screen by means of a A) ball-bearingsupported telescopic rail system. In front of the slide a panel is mounted by means of B) one pair of hinges and C ) one pair of hook and loop fasteners. On the panel a space-consuming. Since the embedding procedure must preserve the translucency of the sections it is obvious that the mounts have to be as thin as possible, creating two problems: 1) the mounts become fragile 2) it has to be possible to study them one by one in front of a display-screen or some other type of transilluminating light source. This shows clearly the necessity for the special way of presentation described in this paper. been fully described elsewhere (Lataster and van Mameren, 1983). Transparent sections with a thickness of 0.4 cm are embedded in catalyzed polyester resin which is poured in a n acrylic container. After hardening the embedding is covered by a second, somewhat smaller, acrylic container in a way that resembles the covering of a microscopical section (Fig. la). Consequently the rims of the hardened mounting are sawn off a t the inner side of the raised border of the smallest container to complete the mount (Fig. lb). The thickness of the finished mounts is approximately 1.1cm. After this the mounts are placed in a vertical storage system containing 1)a cassette, 2) an undercarriage, and 3) a guiding system. 1) The cassette is made of 0.15 cm steel plate (37)with a white, baked-on finish. Each mount is placed vertically in the cassette by DESIGN AND BUILDING OF A VERTICAL STORAGE SYSTEM Before we describe the design and building of the vertical storage system it is necessary to give a summary of the embedding method developed by two of the authors, which has key is written. 544 L.M.A. LATASTER ET AL. -1 3 a Fig. 3.a) Oblique view on the guiding systedundercarriage: 1, aluminum strip; 2, aluminum front piece; 3 , aluminum back piece; 4,ball bearing chamber; 5, steel axle; 6 , aluminum supports (halfway on the table); 7, aluminum strip notched on the underside; 8, springtensioned ball bearing resting in an aluminum support. b) Median-section of the spring-tensioned ball bearing resting in an aluminum support. 1,spring. means of a ball-bearing-supported telescopic rail system (“gliders”; see Fig. 2). Mounted in front of each slide is an acrylic panel (0.2 cm thick), attached on one side by means of a pair of hinges and on the other side with hook and loop fasteners at each corner (Fig. 2). On the panel a key is written by means of a waterproof felt-tipped pen. The referral lines are drawn on the backside to minimize paralax. When the slide is pulled in front of the display screen this panel can be turned away. 2) The cassette is mounted on top of a n undercarriage by means of wing nuts to make it convertible. The undercarriage consists of a) an aluminum front piece containing two ball bearing chambers, b) an aluminum back piece containing two ball bearing chambers, c) two aluminum strips connecting the front and back pieces, and d) a n aluminum strip notched at the underside and mounted as indicated in Figure 3a. 3) The undercarriage makes a gliding motion along the guiding system, which consists of a) four aluminum supports; b) two steel axles, and c) four stops; each consists of a metal ring with Allen screw, a rubber ring (to absorb shocks), and a ring of PerspexR; d) one spring-tensioned ball bearing resting in a n aluminum support. Two supports are mounted at the front and the back of a table, the other two halfway between (Fig. 3a). The axles are mounted in the front and back supports and rest upon the other two (Fig. 3a). The stops are necessary to determine the range between which the undercarriage is able to move. The gliding motion is possible by means of the above-mentioned ball bearing chambers of the guiding system enclosing the axles. The cassette can be moved forward and backward with a handle. The spring-tensioned ball bearing resting in a n aluminum support (Fig. 3a,b) corresponds with the notches of the above-mentioned strip of the undercarriage and enables the undercarriage to be fixed in a position that allows the slide to be as close a s possible to the front of the display-screen. There is one notch for each mount. The complete vertical storage system is placed on top of a table (200 x 100 x 75 cm) with a working surface made of TrespaR (1.8 cm thick). On the table are placed, further, drawn reconstructions of the specific structures in the sections, a display-screen for xrays, acrylic containers to store separated and articulated bones, x-rays, hard copies of C.T. scans, scripts, textbooks, keys, etc. (Fig. 4), and a construction made of pieces of foursided chromed steel tubing (2.5 x 2.5 cm), couplings (T-shaped, corner-shaped, etc.), and planks made of TrespaR to store models, etc. DISCUSSION To obtain insight into the morphology of the human body several learning resources are available to medical students. Besides the “classical” approach of dissecting the hu- A METHOD FOR TEACHING GROSS ANATOMY Fig. 4. The complete module, including A, cassette; B, guiding systemhindercarriage; C, display-screen; D, acrylic containers to store (1) x-rays and hard copies of C.T. scans, (2) scripts, text-books, keys, etc., and ( 3 ) sep- man body in a systematic way (which is not done in our department except by students who take this a s an elective) several other audiovisual media are used. The following list is a summary of the advantages of using transparent sections as a learning resource. The advantages of anatomical sections generally have recently also been stressed by others (Peppler et al., 1983; Boushey and Stultz, 1983). The Use of a Vertical Storage System The advantage of using a vertical storage system in presenting the embedded sections is that they are surveyable, which means that they can easily be studied systematically. The impact-free storage is necessary because of the fragility of the thin mounts (they 545 arated and articulated bones; E, display-screen for xrays; F, construction made of pieces of four-sided chromed steel tubing, couplings, and planks. have to be student-proof) (Bridgman and Hummelbaugh, 1963). The possible need to store a large number of mounts demands a compact design of the cassette. It must be assembled on top of a n undercarriagelguiding system to allow one to study the mounts one by one with transilluminating light in front of a display-screen. Because of the heavy load, the construction and the moving parts of the undercarriage must be strong. The Use of a Convertible Cassette It may be profitable to change the contents of a module. For that reason the cassette should be convertible. Such a conversion can be done quickly by using wing nuts. The use of a limited number of frameworks to house a larger number of modules decreases the 546 L.M.A. LATASTER ET AL. Fig. 5. Detail of the module showing the vertical storage system with one slide pulled in front of the displayscreen and the key panel moved away. A, Three-dimen- sional graphic reconstructions of t h e bony anatomy of the elbow region seen from two directions. costs as compared to the costs of the permanent presentation of all modules in their own framework. sidered to be too time absorbing, the (self) study of sections offers a good alternative. A number of drawings that have been made to reconstruct the series of sections give a clearer understanding of their mutual relation. These drawn reconstructions show the sequence of a series of cross sections in perspective with their serial numbers indicated. A number of separate structures are reconstructed also, such as the bony anatomy (Fig. 5), the muscles, the connective tissue system, etc. The transparent sections are not only useful in teaching at the undergraduate and graduate level. They can-with a n adequate description-also meet the needs of postgraduate training or of continuing education of health-care professionals. This especially holds true for the training which is offered by the self-study of consecutive sections through a given region of the The Possibility of Self-Evaluation The fact that the sections are labelled by placing movable PerspexR panels covered with text in front of each plastic mount, attached on one side by means of a pair of hinges, makes the mounts suitable for selfevaluation: when the panels are moved away, the students can study the sections and are able to check their knowledge (Fig. 5). The Worth of Transparent Sections The advantage of using transparent sections is the ability (in combination with other specimens) to obtain complete awareness of all spatial relations. Where nowadays the dissection of the entire body by each student is frequently con- A METHOD FOR TEACHING GROSS ANATOMY body for those who have to orient themselves in sections, e.g., in C.T. scans of that region. Though the system has been devised as a consequence of the needs induced by the teaching in a student-centered, docent-independent system, it is emphasized that it is useful as well in all kinds of teaching situations, especially in small groups, whether or not in the presence of a teacher. The Construction Time The estimated net production time required to construct the various parts of the described module amounts to cassette 40 hours, undercarriage and guiding system, 40 hours, framework 50 hours, embedding procedure 50 hours, and overlays 40 hours. If one wishes to cover the cross-sectional anatomy, making use of transparent sections in vertical storage systems, our estimation is that about 1,800 hours will be needed. The development of this learning resource has shown to us the necessity of the collaboration of experts in several disciplines (Evans and Eldridge, 1978). In this particular case a medical doctor, a head of the dissection room, a n instrument-maker, and a medical artist were involved. ACKNOWLEDGMENTS The authors are indebted to Th. Gulikers (instrument-maker) for his technical advice 547 and building both the framework and the vertical storage system for the mounts. LITERATURE CITED Boushey, D.R., and W.A. Stultz (1983) The preparation' of human cross sections. Anat. Rec., 207t379-383. Bridgman, C.F., and F.A. Hummelbaugh (1963) Plastic embedded specimens in medical teaching. Med. Biol. Ill. 13t177-185. Drukker, J., H. van Mameren, H.W.M. van Straaten, F. Thors, J.C. van der Wal, E.L.M.J. Wiertz-Hoessels, and W.G.M. Witkam (1981) The teaching of anatomy in a non-traditional medical curriculum. Acta Anat., lllt35-36. Evans, E.M., and W.S. Eldridge (1978) Audiovisual media, a combined operation. J. Audiovis. Media Med., 1:140-142. Lataster, L.M.A., and H. van Mameren (1983) Eine Methode zur Einbettung von Aufbellungspraparaten in Kunstharz. Praparator, 29:165-172. Peppler, R.D., T.E. Kwasigroch, and M.W. Hougland (1983) Cross-sectional anatomy: preparation of teaching specimens. Anat. Rec., 206:341-344. Mc. Pheeters, V. (1979) Learning resource centers-past, present and future. J. Audiovis. Media Med., 2:173174. Pallie, W., and E. Brain (1978) Modules in morphology for self study: a system for learning in a n undergraduate medical programme. Med. Educ., 12:107-113. Piechocki, R. (1979): Makroskopische Praparationstechnik, 3e Auflage. Gustav Fischer Verlag, New York, Vol. I Wirbeltiere, pp. 245-272.