I'm sorry to say in all my dictionaries is „cervical, -lis“ a post-classic latin word. The only literal sense is pillow. The traduction is grammatical O.K.
Vale
Lupellus
same thing for me. Cervical, pl. cervicalia = coussin. I suspect this sentence, with its "the friend of the brother of the queen", to be some kind of nonsensical purpose-made "exercise sentence" such as "my taylor is rich".