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 o'clock to 5 o'clock position in the right eardrum and the 7 o'clock to 8 o'clock position in the left eardrum. The apex of the cone is at the most depressed part of the tympanic membrane, known as the umbo. The absence of a cone of light does not necessarily signify
Inferior tympanic artery Inferior tympanic artery The inferior tympanic artery is a small branch of the ascending pharyngeal artery. It is a small branch which passes through a minute foramen in the petrous portion of the temporal bone which is called tympanic canaliculus or inferior tympanic canaliculus, in company with the tympanic branch of the glossopharyngeal nerve, to supply the medial wall of the tympanic cavity and anastomose with the other tympanic arteries. In the case of a missing or underdeveloped cervical ICA, the Inferior tympanic artery can provide collateral ICA circulation by reversing flow of the caroticotympanic artery (embryologic hyoid artery). This