What is "splenae"?

[Odin_Himself]

Dear Sirs/Madams!

I am so sorry to post such a silly question, but I did not manage to an answer myself.

The question is: "What is splenae (supposedly a muscle) and where is it located?"

[Hayden-William Courtland]

This is likely being used as a general term for the splenius capitis and splenius crevicis. They are superficial muscles on the posterior neck.