Background: The elliptical excision is a common surgical procedure. The dermatologic literature predominantly describes an excisional geometry with a 3:1 length:width ratio and an apical angle of 30 degrees.
Objective: To analyze the elliptical excision by applying mathematical principles and define the apical angle and its relationship to the length:width ratio.
Methods: We examined numerous examples of elliptical excisions as presented in the dermatologic literature. We analyzed the geometry of the excisions and defined it mathematically.
Results: The apical angle of a 3:1 elliptical excision is not 30 degrees. The true apical angle varies from 37 degrees to 74 degrees depending on excisional geometry.
Conclusion: The commonly presented apical angle of 30 degrees is incorrect and does not reflect the true apical angle of elliptical excisions.