page_title: Phineas Gage
section_title: Extent of brain damage
hierarchical_section_title: Phineas Gage / Mental changes and brain damage / Extent of brain damage
caption_attribution_description: English: The injury of Phineas Gage, based on Ratiu (2004), with frontal lobe shown in red. Summary of Ratiu's analysis is available at John Darrell Van Horn (2012).
context_page_description: Phineas P. Gage was an American railroad construction foreman remembered for his improbable survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior over the remaining 12 years of his life‍—‌effects sufficiently profound that friends saw him as "no longer Gage."
  Long known as the "American Crowbar Case"‍—‌once termed "the case which more than all others is calculated to excite our wonder, impair the value of prognosis, and even to subvert our phys­i­o­log­i­cal doctrines" ‍—‌Phineas Gage influenced 19th-century discussion about the mind and brain, par­tic­u­larly debate on cerebral local­i­za­tion, ​​ and was perhaps the first case to suggest the brain's role in deter­min­ing per­son­al­ity, and that damage to specific parts of the brain might induce specific mental changes.
context_section_description: Debate about whether the trauma and sub­se­quent infection had damaged both of Gage's frontal lobes (left and right), or only the left, began almost immedi­ate­ly after his accident.​​ The 1994 con­clu­sion of Hanna Damasio et al., that the tamping iron did physical damage to both lobes, was drawn not from Gage's skull but from a cadaver skull dig­i­tal­ly deformed to match the dimen­sions of Gage's​​​​‍—‌and made a priori assumptions about the location of Gage's internal injuries and the exit wound which in some cases contradict Harlow's observations. Using CT scans of Gage's actual skull, Ratiu et al. and Van Horn et al. both rejected that conclusion, agreeing with Harlow's belief‍—‌based on probing Gage's wounds with his fingers‍—‌that only the left frontal lobe had been damaged.
  In addition, Ratiu et al. noted that the hole in the base of the cranium (created as the tamping iron passed through the sphenoidal sinus into the brain) has a diameter about half that of the iron itself; combining this with the hairline fracture beginning behind the exit region and running down the front of the skull, they concluded that the skull "hinged" open as the iron entered from below, then was pulled closed by the resilience of soft tissues once the iron had exited through the top of the head.
  Van Horn et al. concluded that damage to Gage's white matter (of which they made detailed estimates) was as or more significant to Gage's mental changes than cerebral cortex (gray matter) damage. Thiebaut de Schotten et al. estimated white-matter damage in Gage and two other case studies ("Tan" and "H.M."), concluding that these patients "suggest that social behavior, language, and memory depend on the coordinated activity of different [brain] regions rather than single areas in the frontal or temporal lobes."
caption: The left frontal lobe (red), with Ratiu et al.'s estimate of the tamping iron's path[R1]