independentstudy

I apologize in advance if the following are stupid questions. 1. In the text, the following is written in a table regarding the innervation of the rhomboid minor, "Dorsal scapular nerve (C5, posterior)." What is "posterior" referring to? So far, my understanding has been that if you see something like, e.g., "Dorsal scapular nerve (C5)," written out to indicate the innervation of a muscle, "C5" is referring to the fact that the innervation by the dorsal scapular nerve to that muscle is derived from the fifth cervical segment of the spinal cord. In following this interpretation, is "posterior" serving to specify that the innervation is derived from the posterior portion of the fifth cervical segment of the spinal cord? 2. In the same text, I've seen "C3-C4" written as part of the description of the innervation for a muscle. Is there a particular reason the author wrote "-" instead of "and?" Is it just to save ink? Thank you.