Verse 38 is the companion information to the final note in verse 37. We have a comparison between the casualty rates of the Lamanites and the Nephites. The Lamanites do not have body armor, and the Nephite army does. We do not know if all of the Nephites have the armor, or only the forces that Moroni brought with him. This might have been the case as the rest of the army was raised from the local land, and might not have had the armor previously prepared.
The result is a greater number of casualties among the Lamanites. Each force was similarly equipped, but the body armor of the Nephites protected them from more serious injuries. Nevertheless, the hand to hand combat did expose them to cuts on their arms and legs, and the text indicates that there were men lost from loss of blood through the cuts on the unexposed parts of the body.
What we are not told is the relative size of the armies. While it is tempting to see the Nephites as the larger army because they were fighting in their own lands, it is also quite possible that the Lamanite army was much larger. This would explain the need for Moroni’s tactic of division. Had the Lamanite army been smaller, Moroni might have simply met them, or the size of the opposing force would have intimidated a retreat as it had in Jershon. The implications of the text suggest that it was the Lamanites who had the superior numbers, and that the tactics of division and armament made the different in the battle.