Computer Methods and Programs in Biomedicine 26 (1988) 71-74Elsevier

CPB 00845

Section II . Systems and programs

Anatomy helper : computer-assisted anatomy instruction

William Simon

Department of Biophysics, University of Rochester, Rochester, NY, U.S.A .

A combination of transparent pictorial overlays with conventional computer displays, and a simple program, provides avery effective method of teaching and reviewing anatomy .

Computer-aided instruction ; University of Rochester Medical Center ; Anatomy instruction ; Pictorial overlays

The University of Rochester Medical Center has avery active program in computer-assisted medicaleducation. Some of the computer programs havebeen obtained from commercial sources, othersfrom colleagues in other universities, but we foundthe need to develop a program to review humananatomy. We wanted the computer to mimic therole of a teacher asking students to locate particu-lar anatomical features or alternatively to displaya feature of anatomy and ask for its name.

In order to do this it is necessary to providebetter quality pictures than can be produced bythe graphics system normally used on IBM PCs * .We therefore made transparent plastic overlay pic-tures which are stuck to the face of a standarddisplay and backlighted by filling the screen withan almost solid raster. A mouse cursor visiblethrough the transparency is used to point to fea-tures (Fig . 1). The student responds to requests toidentify anatomical features by pointing to themand clicking the button on the mouse .

The student is allowed two tries for each fea-

Correspondence : William Simon, Department of Biophysics,University of Rochester Medical Center, Rochester, NY 14642,U.S.A .* Trademark IBM Corporation .

0169-2607/88/$03.50 © 1988 Elsevier Science Publishers B .V. (Biomedical Division)

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Lure. If he gets both wrong the computer intervenes by backlighting the correct area . He is al-most immediately tested on it again . Maximumuse is made of a number of standard pedagogicaltechniques such as intermittent reinforcementmixed with antagonistic nagging when the studenthas made an incorrect identification .

The method of choosing the questions is asfollows : On each picture up to 15 anatomicalfeatures are designated. Initially, the student isasked about three fairly prominent, well-known,easily identified features . When he identifies onecorrectly, he is rewarded by a cheerful chirp . Anincorrect identification produces an ominousgrowling sound. An incorrect answer also in-creases the frequency with which that feature willbe presented. A correct answer reduces thefrequency for repeating that feature, but thefrequency is never allowed to fall to zero. Ascorrect identifications are made new items areadded to the question set . Gradually, the initialpool of three prominent features is replaced by awider variety of less well-known, less obvious fea-tures. Incorrect identifications are queried moreoften, while correct identifications are suppressedbut never eliminated .

Every now and then the student is reinforcedby having his score displayed. He can also inter-

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rupt the program and ask for his score on the listof individual features. In this way, he spots anythat he is consistently getting wrong .

In the reverse phase of the program, the nam-ing phase, the computer backlights the anatomicalfeature and the student is asked to type in itsname (see Fig . 2) .

Some flexibility in name recognition is allowed,i.e. interchanged words. After much debate be-twepn clinicians and anatomy instructors, most ofwhom insisted on correct spellings, and the authorof the program, who spells very poorly, the follow-ing compromise was developed : The computerwill accept a recognizable misspelling, but willthen harrass the student to try to spell the particu-lar feature correctly . Full credit is achieved onlyby correct spelling . The algorithm for identifying

Fig. 1 . The screen during the feature location phase .

incorrectly spelled words is a fairly complicatedone and will not be discussed here .

The transparencies which are the key to thissystem were used because they are an inexpensiveand flexible method of displaying a high-qualitypicture. The computers used are IBM PCs withstandard color graphics . While there are otherdisplays capable of much higher resolution andfiner gray levels, the cost of these is considerableand 12 units were needed . For this, and otherreasons, it was felt that, if at all possible, standardPC units should be used. The overlays make thispossible .

The method of producing the overlays is quitesimple. Most standard office copiers (includingcolor copiers) will accept transparent sheets thatare usually used for overhead projectors . Sources

of the pictures have been locally available photo-graphs, drawings, uncopyrighted books or booksfor which copyright permission has been obtainedfrom the publishers.

Each transparency has, in addition to the ap-propriate anatomical structure, three locatingmarks. The program starts with instructions to theuser to align the overlays with three marks dis-played on the computer screen . This allows forvariations in individual displays even up to sub-stantial changes in the size of the screen such asmight occur in switching between different typesof displays .

When the overlay is first used, the author usesthe mouse to identify for the computer the areasbelonging to each anatomical structure . Theseareas are entered as small rectangles which can be

Fig. 2. The screen during the feature naming phase .

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juxtaposed or superimposed to fit the usually non-rectangular shapes of anatomical features . Coordi-nates for each feature are saved on the programdisk.

Up to fifteen rectangular areas are allowed foreach anatomical feature . Irregular anatomical areascannot be exactly defined by rectangles, but withinthe accuracy set by easy visibility and the slightparallax error, this seems to be adequate. It is, forexample, comparable to pointing to a structure ina brain section with a pencil, but without actuallytouching the surface. The process of outlining astructure is not particularly tedious . A few sec-onds suffices for each .

The three locating marks discussed above aresimply penciled crosses made on the original pho-tographs and entered into the stored table as

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structure number zero, which is used only in theinitial setup phase .

This system sounds very simple and conceptu-ally it is. It has, however, some of the captivatingquality of video games. Students and visitors whohave tried it find that they become compulsively

entrapped by the game nature of the computerinteraction. Thus, it is far more reinforcing andless frustrating than learning anatomy from atextbook. It is proving to be a very effectiveaddition to our library of computer-assisted in-struction methods.