If effective scientific communication is like a well-designed and smoothly operating machine, then grammar – the accepted system of rules by which words are formed and put together to make sentences – forms the nuts and bolts that hold it all together. The individual fasteners of punctuation, capitalization, and such may seem simple and unexciting to look at, but they are undeniably important if the machine is to hold together and function properly.

In this chapter, we suggest ways of avoiding and correcting some common mechanical mistakes that scientific writers tend to make. For further advice, style manuals of special utility for biomedical writers include the Publication Manual of the American Psychological Association (2010), the AMA Manual of Style (2007), and the Council of Science Editors’ Scientific Style and Format (2006). All are updated at intervals; be sure to check for the latest edition.

Punctuate for clarity

Punctuation has one purpose – to help the reader understand the structural relationship within (and thus the intention of) a sentence. For this reason, the best approach to punctuation is almost always the simplest. Punctuation should be almost automatic. If you are puzzled over how to punctuate a particular sentence, you probably have created a sentence that will puzzle readers too, no matter how you punctuate it. Rewrite the sentence in a form that requires only simple punctuation.