Boundaries of anterior recess in ear
Reading File
Finding Sources
Finding Sources
Reading File
Finding Sources
Finding Sources
Reading File
Finding Sources
Finding Sources
Finding Sources
Searching the Web
anterior recess external auditory canal boundaries anatomy ENT
I now have comprehensive information from both the textbook and web sources. Here is the complete answer:
Anterior Recess of the External Auditory Canal (EAC)
The anterior recess (also called the anteroinferior recess or pretympanic recess) is a wedge-shaped pocket in the deep bony part of the external auditory canal (EAC). It is formed because the anterior wall and floor of the bony EAC are approximately 6 mm longer than the posterior wall and roof.
Boundaries
| Boundary | Structure |
|---|---|
| Medially | Tympanic membrane (anteroinferior quadrant) |
| Laterally | Isthmus of the bony EAC (the narrowing ~5-6 mm lateral to the TM, where a prominence of the anterior canal wall reduces the canal diameter) |
| Anteriorly / Floor | Anteroinferior wall of the bony EAC (formed by the tympanic part of the temporal bone), which dips forward to create the pocket |
| Posteriorly | The plane of the rest of the tympanic membrane / canal |
In essence: deep to the isthmus, the anteroinferior portion of the canal dips forwards, forming a wedge-shaped anterior recess between the tympanic membrane and the anterior canal wall. - Scott-Brown's Otorhinolaryngology, Vol. 2
Key Points
- It lies medial to the isthmus of the bony EAC (isthmus is ~5-6 mm from the TM).
- It is the deepest, most dependent part of the bony EAC - acts as a "cesspool" for discharge, debris, and cerumen.
- It is hidden from direct otoscopic view by the anterior canal bulge (the prominent anterior wall of the EAC). A camera or angled telescope is required to visualize it.
- The foramen of Huschke (a developmental deficiency in the anteroinferior bony EAC) may open into this recess in children or occasionally adults, allowing spread of infection to/from the parotid gland.
- It is a difficult spot for access both clinically and surgically, and is a common site for missed cholesteatoma or retained keratin.
Clinical Relevance
- Cholesteatoma, cerumen plugs, and foreign bodies tend to collect here because of poor access.
- During canaloplasty or ear surgery, the anterior canal wall prominence must be drilled down to adequately expose this recess.
- Otoscopy with a camera or Hopkins rod gives better visualization than a standard otoscope. - Scott-Brown's Otorhinolaryngology, Vol. 2
This is a shared conversation. Sign in to Orris to start your own chat.