Scientific papers of biomedical journals are divided into two types: on the one hand those the authors write in a spontaneous way and then send to the journal for its publication (e.g. original articles, case reports and letters to the editor) and on the other hand those requested to the authors by the journals (e.g. editorials and reviews). While the former are subjected to peer review system, the latter have a perfect passport for publication due to their commission nature.
In this paper we review the «background» (what is said) of each major type of article, reviewing with particular depth the different sections of original articles: title, abstract, introduction, materials and methods, results, discussion, bibliography. Knowing the "background" of the articles is key to start the preparation and submission of a manuscript to a biomedical journal.