Cranial trauma or a head injury was a term used for when a person was hit on the head violently or suffered from an injury from hitting their head.
In 2369, Dr. Julian Bashir examined Chief Miles O'Brien after he had been found to be suffering from aphasia. Bashir could not find any signs of cranial trauma, which, along with a stroke, was usually a possible cause of aphasia. It was later discovered that O'Brien had contracted aphasia from an aphasia device planted on the station in 2351 by Bajorans when it was under Cardassian rule. (DS9: "Babel")
In 2371, a representation of Benjamin Sisko that Bashir encountered in his mind following a Lethean telepathic attack told a nurse to give a patient with cranial trauma inpedrezine after treatment with an osteogenic stimulator. (DS9: "Distant Voices")