Posterior sinus of the middle ear

Area of Science:

• Otolaryngology
• Anatomy
• Surgical Anatomy

Background:

• The posterior sinus of the middle ear is an anatomical region with limited prior description.
• Understanding its relationship with the sinus tympani is crucial for otologic surgery.

Purpose of the Study:

• To define the anatomical characteristics of the posterior sinus.
• To elucidate its relationship with the adjacent sinus tympani.

Main Methods:

• Analysis of 51 human cadaveric temporal bone specimens.
• Detailed measurement of posterior sinus depth and width.
• Assessment of the intervening structure between the posterior sinus and sinus tympani.

Main Results:

• The posterior sinus opening measures 1.5 mm or less in width and is 1 mm or less in depth.
• A bony ridge separated the posterior sinus from the sinus tympani in 82% of specimens.
• A bony sheet or confluent recess was observed in 10% and 8% of specimens, respectively.

Conclusions:

• The posterior sinus is a distinct anatomical entity, smaller than previously assumed.
• A bony ridge, not the ponticulus, typically separates the posterior sinus from the sinus tympani.
• This detailed anatomical knowledge benefits otologic surgeons in managing posterior tympanum pathologies.