Deciphering the Medial Wall of the Middle Ear

OtoPrep Right Middle Ear Endoscopic Anatomy

Deciphering the Medial Wall of the Middle Ear: An Interactive Anatomy Guide

The human auditory system is a fascinating and complex structure, and its central chamber, the middle ear, is a focus for otolaryngology examinations and clinical diagnosis. This article provides an in-depth look at the medial wall of the middle ear, also known as the labyrinthine wall, which features prominently in Otolaryngology Examinations.  

How well do you know the medial wall of the middle ear?

Identify these structures on the image above:
1. Prussak's Space
2. Lateral Process of Malleus
3. Manubrium of Malleus
4. Umbo of Malleus
5. Long Process of Incus
6. Lenticular Process of Incus
7. Stapedial Ligament
8. Posterior Sinus
9. Pyramidal Eminence
10. Stapes Footplate
11. Ponticulus
12. Sinus Tympani
13. Subiculum
14. Promontory
15. Round Window Niche
16. Finiculus
17. Eustachian Tube
18. Processus Cochleariformis
19. Tensor Tympani
20. Jacobson's Nerve.

The Vital Structures

  • Prussak's Space: A crucial area prone to cholesteatoma formation, bordered by Shrapnell's membrane and the scutum.
  • Lateral Process of Malleus: Visible during otoscopic examination, this is a key landmark in the tympanic membrane.
  • Manubrium of Malleus: This handle-like structure transmits sound vibrations to the incus.
  • Umbo of Malleus: The concave tip of the manubrium and a central examination point for eardrum retraction.
  • Long Process of Incus: Essential for sound conduction, this process articulates with the stapes.
  • Lenticular Process of Incus: Facilitates the vibration transfer from the incus to the stapes.
  • Stapedial Ligament: Provides stability for the stapes, the smallest bone in the body.
  • Posterior Sinus: A depression with surgical significance in the tympanic cavity.
  • Pyramidal Eminence: Houses the stapedius muscle, critical for dampening sounds.
  • Stapes Footplate: Fits into the oval window and is central to sound transmission to the inner ear.
  • Ponticulus: A small bony bridge in the posterior wall of the tympanic cavity.
  • Sinus Tympani: A deep recess behind the oval window in the medial wall of the tympanic cavity.
  • Subiculum: A small area located at the entrance to the sinus tympani.
  • Promontory: A rounded prominence on the medial wall of the tympanic cavity, formed by the first turn of the cochlea.
  • Round Window Niche: A small hollow area in the medial wall of the tympanic cavity that houses the round window of the cochlea.
  • Finiculus: A small, cord-like structure in the tympanic cavity.
  • Eustachian Tube: A tube that connects the middle ear to the nasopharynx, allowing for the equalization of pressure on either side of the eardrum.
  • Processus Cochleariformis: A small, hook-like bone in the tympanic cavity that serves as a pulley for the tendon of the tensor tympani muscle.
  • Tensor Tympani: A small muscle in the middle ear that dampens the vibrations of the tympanic membrane by pulling on the manubrium of the malleus.
  • Jacobson's Nerve: Also known as the tympanic nerve, this is a branch of the glossopharyngeal nerve that provides sensory innervation to the middle ear.

These structures play crucial roles in the transmission of sound from the external environment to the inner ear, where it is converted into electrical signals and interpreted by the brain. Understanding their anatomy is essential for otolaryngologists, as it aids in the diagnosis and treatment of various ear conditions.

Understanding the Middle Meatus and Tympanic Cavity Segments

The middle meatus, a key component of nasal anatomy, and various segments of the tympanic cavity play integral roles in the function and health of the ear and nose. Detailed knowledge of these structures is essential in otolaryngology, particularly for understanding pathologies and surgical approaches.

Middle Meatus and Tympanic Cavity Segments

The middle meatus can be divided into several segments, including the hypotympanum, epitympanum, mesotympanum, protympanum, and retrotympanum. Each segment has distinct anatomical features and functions:

  • Hypotympanum: Located inferior to the tympanic membrane, this crescent-shaped space at the bottom of the middle ear is crucial for the drainage and function of the middle ear.
  • Epitympanum: Also known as the attic, the epitympanum is the most superior portion of the tympanic cavity, containing important auditory ossicles.
  • Mesotympanum: The central part of the tympanic cavity, the mesotympanum houses most of the middle ear's crucial structures and is pivotal for sound transmission.
  • Protympanum: Anterior to the tympanic cavity, the protympanum contains the bony portion of the Eustachian tube, playing a role in ear ventilation and pressure regulation.
  • Retrotympanum: The retrotympanum features various sinuses and recesses, making up the complex posterior aspect of the tympanic cavity.

For otolaryngologists and students, an in-depth understanding of these segments aids in the accurate diagnosis and effective treatment of ear and nasal conditions.

Interactive Image With Solutions


  1. IMAIOS - Middle Nasal Meatus
  2. ScienceDirect - Middle Ear
  3. Radiopaedia - Epitympanum
  4. Radiopaedia - Mesotympanum
  5. Radiopaedia - Protympanum
  6. Wikipedia - Nasal Meatus
  7. Radiopaedia - Hypotympanum