ⓘ Cone of light

                                     

ⓘ Cone of light

The cone of light, or light reflex, is a visible phenomenon which occurs upon examination of the tympanic membrane with an otoscope. Shining light on the tympanic membrane causes a cone-shaped reflection of light to appear in the anterior inferior quadrant. This corresponds to the 4 oclock to 5 oclock position in the right eardrum and the 7 oclock to 8 oclock position in the left eardrum. The apex of the cone is at the most depressed part of the tympanic membrane, known as the umbo.