MacEwen triangle
Last revised by Francis Deng ◉ on 14 Mar 2021
Citation, DOI & article data
Citation:
Gaillard F, Deng F, Weerakkody Y, et al. MacEwen triangle. Reference article, Radiopaedia.org (Accessed on 29 Jan 2023) https://doi.org/10.53347/rID-1635
rID:
1635
Article created:
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19 times by 7 users - see full revision history
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Synonyms:
- Macewen's triangle
- MacEwen triangle
- MacEwen's triangle
- Suprameatal triangle
- Mastoid fossa
- Foveola suprameatica
- McEwen's triangle
- MacEwan's triangle
- McEwan's triangle
- MacEwens triangle
The MacEwen triangle (also called the suprameatal triangle or mastoid fossa) is a surgical landmark on the surface of the temporal bone just superior to the external auditory canal used to locate the level of the mastoid antrum.
Three lines form the triangle:
- superior: inferior temporal line/supramastoid crest extending back from the posterior root of the zygomatic process of the squamous temporal bone
- anteroinferior: tangent extending up from the posterosuperior border of the external acoustic meatus, including the suprameatal spine of Henle
- posterior: vertical tangent extending up from the posterior border of the external auditory canal
On this page:
History and etymology
It is named after Sir William MacEwen (1864-1924), Scottish surgeon.
Clinical importance
The mastoid antrum lies 1-2 cm deep to the triangle in the adult and thus serves as a landmark when performing a cortical mastoidectomy.
Related pathology
The cortical bone is thin in this area and thus susceptible to subperiosteal abscess formation in cases of coalescent mastoiditis.
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