The MacEwen triangle, also known as the suprameatal triangle or mastoid fossa, is a crucial surgical landmark located on the surface of the temporal bone, just superior and posterior to the external auditory canal (ear canal). It serves as a guide for surgeons to locate the mastoid antrum during surgical procedures like mastoidectomy.
Importance and Location
- Surgical Landmark: The primary significance of the MacEwen triangle is as a surface landmark guiding surgeons to the mastoid antrum, a key cavity within the mastoid bone.
- Location: It is found on the mastoid process of the temporal bone. Its boundaries are generally defined by:
- The posterosuperior border of the external auditory canal (ear canal).
- The supramastoid crest (a bony ridge running posteriorly from the ear canal).
- A tangent drawn superiorly to the posterior aspect of the ear canal.
- Antrum Access: By understanding the anatomy of the MacEwen triangle, surgeons can accurately and safely access the mastoid antrum during surgical interventions aimed at treating infections or other pathological conditions of the middle ear and mastoid.
Why is it Important?
- Surgical Precision: Accurate identification of the MacEwen triangle allows for a direct and minimally invasive route to the mastoid antrum, reducing the risk of damage to surrounding structures.
- Minimizing Complications: Knowing the precise location of the antrum helps avoid injury to vital structures, such as the facial nerve or the sigmoid sinus, during mastoid surgery.
- Mastoidectomy: During mastoidectomy (surgical removal of the mastoid air cells), the MacEwen triangle is a constant reference point for the surgeon.
