The most common site of perilymph fistula -

Ans. is 'b' i.e., Oval windowPerilymph fistulao In this condition, perilymph leaks into the middle ear through the oval or round window.o Perilymphatic fistula (so positive fistula test) may occur due to a defect in one of three locations:-1) Oval - window (most common site)Stapedectomy surgery (for otosclerosis)Head trauma or Barotrauma (Pressure injury)Acoustic traumaRound window (rupture of round window membrane)Barotrauma SCUBA diving, airplane pressurizationCongenital malformations (mondini dysplasia)Otic capsuleAnother possible location for a fistula is in the bone of the ear (the otic capsule). This is a rare condition where the bone between the ear and brain area is missing or thin, causing symptoms very similar to that of round or oval window fistula. Causes areSuperior canal dehiscence syndromeCholesteatomaFenestration surgery (surgically created window in horizontal SCC)Erosion of Horizontal (lateral) SCC due to any causeTemporal bone fractureMicro fissure