Author(s)
Mohamed A. Alhussaini, MD
Jameson K. Mattingly, MD
Stephen P. Cass, MD, MPH
Affiliation(s)
Abstract:
Hypothesis: The suprameatal crest provides a reliable landmark to the middle fossa dura.Background: Surface anatomy of the temporal bone is used to guide mastoid surgery, but studies investigating theselandmarks are limited. The aim of this study was to examine the anatomical relationship of the middle fossa dura to thesuprameatal crest.Methods: 28 fresh hemi-cephalic temporal bones were prepared by drawing 4 lines along the mastoid including thesuprameatal crest (line 1), one line 5 mm above (line 2) and one 5 mm below line 1 (line 3), and at Reid’s base line (line4). 4 points were marked along these lines anterior to posterior 3 mm apart. A 1 mm bur was used to drill perpendicular tothese points to examine the relationship to the middle fossa dura.Results: The dura was found below line 1 in 3.57% at point 1, 3.57% at point 2, 7.14% at point 3, and 17.9% at point 4.The dura in line 2 was found below point 1 in 57.14%, point 2 in 50%, point 3 in 60%, and point 4 in 68%. Only onespecimen (3.57%) had dura lying completely below line 3.Conclusions: The dura of the middle fossa lies above the suprameatal crest in 95% of specimens and at least 5 mm abovein nearly half. The slope of the dura also becomes more inferior more posteriorly. This indicates the suprameatal crest is areliable landmark for the middle fossa dura.Define Professional Practice Gap and Educational Needs: Limited studies defining the relationship of the middle fossadura to surface landmarks of the temporal bone, such as the suprameatal crestLearning Objective: Understand the relationship of the middle fossa dura to the suprameatal crestDesired Result: Optimize the safety of mastoid surgery regarding localization of the middle fossa duraIRB or IACUC Approval: Exempt