Can a trama to the head & neck "awaken" an archanyiod cyst?

I don't know: what you mean by "awaken" Arachnoid cysts are mostly ASYMPTOMATIC and are FOUND incidentally when advanced imaging is obtained after head/neck trauma! Hope this is helpful Dr Z

Arachnoid Cysts: These are usually cysts that you were born with or can develop from other causes. They are usually asymptomatic although when you have any problems that can increase the pressure of the cerebrospinal fluid you could have symptoms such as headaches back pain vomiting depending on where the cyst is located and what it is pressing on. Most of the time they are asymptomatic,