TREPHINATION By N., Sam M.S. - 48 noun. a surgical process wherein a disk of bone is excised, generally from the cranium, with a circular tool having a saw-like edge. TREPHINATION: "Trephination of the skull is thought to be one of the earliest forms of surgery to have existed." Related Psychology Terms MENTAL RETARDATION (CAUSES) Using the Hamilton Depression Rating Scale: A Case Study on Grief ANORTHOSCOPE LANGUAGE (Psycholinguistics) SCHIZOPHRENIA (OTHER TYPES) Comparison of Assessment Tools Discrimination and Mental Illness in the LGBT Population ADOLESCENCE (Theories) CEREBRAL CORTEX MANIC-DEPRESSIVE REACTION (CIRCULAR AND MIXED TYPES) Cite this page: N., Sam M.S., "TREPHINATION," in PsychologyDictionary.org, April 29, 2013, https://psychologydictionary.org/trephination/ (accessed June 25, 2022).