Dashes and hyphens

Dashes and hyphens are used all over Radiopaedia.org and should be used in a particular way to ensure cohesive use across the site.  

Dashes and hyphens

In publishing, there are distinct differences between the following which usually are of different lengths:

• minus sign: used exclusively to represent a minus sign
• hyphen: used to connect words in hyphenation
• en-dash (width of an n): used to connect numbers or compound words
• em-dash (width of an m): used instead of commas and parentheses

In reality, we just have one character to use (the minus sign on the keyboard).

Minus and hyphen

The minus sign and hyphen scenarios above should be obvious use-cases.  

En-dash

When using the en-dash on Radiopaedia.org, we follow recognised standards recognised standards (Chicago manual of Style) and state that there should be no space on either side of the dash:

• numeric ranges: incidence is 4-16%
• compound words: high-signal
• combinations of imaging modalities: PET-CT

Em-dash

In publishing, the longer dash (em-dash) is employed without surrounding spaces. On Radiopaedia.org, because the majority of people wouldn't be able to add the em-dash, we have taken the pragmatic approach of replacing it with a " - ", which is a space, then a minus sign, then space. It should be used in place of a comma or parenthesis:

• the use of the em-dash replaces normal parentheses - as can be seen here - when in the central part of the sentence