The impact of alternating dissection on student performance in a medical anatomy course: are dissection videos an effective substitute for actual dissection?

The way in which anatomy is taught to first year medical students at the University of North Carolina at Chapel Hill was recently changed, so that first year students are now divided into two groups that dissect alternately. The effect of this change on both written and practical test performance was analyzed by comparing grades from 2004 with those from the previous year (2003), when students performed all the dissections. A statistically significant decrease (P < or = 0.05) from 2003 was noted on three of the four written test scores in 2004, while practical examination scores in 2004 fluctuated from lower to higher than those in 2003, depending on the unit of material being covered. However, the number of students failing each of the examinations (written and practical combined) was statistically greater on only one of the four examinations in 2004. Scores of the two groups dissecting alternately in 2004 were essentially the same on the practical examinations. There was no difference in the number of questions answered incorrectly between these two groups in the two practical examinations where comparisons were made. Furthermore, students who dissected a particular structure did not score significantly better on practical questions concerning that structure than students who had not dissected it. The effect of the availability of step-by-step dissection videos on student practical examination scores is also discussed. We conclude that the change in the curriculum had a significant impact on the students' written examination performance, given the same material in the course. The reasons for this include student course load, increased need for self-study, and a loss of a learning opportunity in the dissection laboratory, all of which affect student comprehension and retention of the material and their ability to use it in problem solving.