Retrotympanum and Round Window Region

Retrotympanum is the space in middle ear posterior to annulus of tympanic membrane. It comprises various recesses and structures lodged within the posterior wall (mastoid wall) of tympanic cavity. The inferior retrotympanum includes the round window region and is studied using endoscopic visualisation.

With the advent of endoscopes we have understood middle ear anatomy in a much better way. These days endoscopes are routinely used for middle ear surgeries, even for cholesteatoma removal and stapedotomy. When microscope and endoscope are used together, we term it COMET surgery in ENT.


Check the images uploaded for a concise anatomy on retrotympanum and inferior retrotympanum. You will also be able to see easily reproducible diagrams. For your convenience, we have uploaded a PDF of the topic.

The above topics are very important for your theory as well as practical exam. A question on endoscopic anatomy of middle ear will need details about retrotympanum and inferior retrotympanum in addition to protympanum, epitympanum, mesotympanum and hypotympanum.

Above all, only with a sound anatomy of the region will your middle ear surgeries be successful. Complete clearance of disease from the recesses of retrotymanum ensures no recurrence.

image gallery
important recesses
  1. Facial Recess
  2. Lateral Tympanic Sinus
  3. Sinus Tympani
  4. Posterior Tympanic Sinus
important bony ridges
  1. Chordal ridge
  2. Pyramidal ridge
  3. Suprapyramidal ridge
  4. Ponticulus
  5. Subiculum
  6. Funiculus
  1. Pyramidal eminence
  2. Chordal eminence
  3. Styloid eminence

Our notes have been made after extensive search in NCBI bookshelves and other standard textbooks. Please write to us at to let us know your comments. Do let us know if there is any error in the pictures or description.

  1. Indian Journal of Otolaryngology and Head & Neck Surgery
  2. Journal of Visualized Experiments
  3. Thieme Endoscopic Ear Surgery
  4. Otolaryngology – Head and Neck Surgery
  5. Researchgate

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