Related Experiment Video
Updated: Oct 17, 2025

Microtensiometer for Confocal Microscopy Visualization of Dynamic Interfaces
Published on: September 9, 2022
Unmitigated negative nasopharyngeal pressure is associated with attic retraction pocket formation: LaPlace's law in
Nilesh H Mahajan1, H Vijayendra1, Vinay Kumar Vijayendra1
1Vijaya ENT Care Centre, Superspeciality Otology Centre, Bangalore560003, India.
Background:
Decades of clinical observation have led our subspecialty team to suspect that negative nasopharyngeal pressure is associated with attic retraction pocket formation. Furthermore, LaPlace's law, which states that the pressure within a sphere varies with the inverse of the radius, provides the dynamic explanation for why the attic area of the tympanic membrane tends to retract more frequently than the pars tensa.
Methods:
The attic retraction pockets of 154 patients were classified into grades of severity (grades I-V). Impedance audiometry of middle-ear pressure was measured in the resting state, and after sniffing, swallowing and the Valsalva manoeuvre.
Results:
Negative nasopharyngeal pressure (sniffing) caused a diminution of middle-ear pressure of -5 daPa on average in normal ears, and of -24 daPa to -45 daPa for tympanic membranes with attic retraction pockets of grade I to grade V.
Conclusion:
Attic retraction pockets are associated with greater collapse of middle-ear volume when negative pressure is created in the nasopharynx. LaPlace's law, and the composition of the pars flaccida, suggests an explanation for why the attic region retracts more than the pars tensa.
More Related Videos
09:31Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism
Published on: February 14, 2022
07:41Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse
Published on: April 17, 2019
Related Concept Videos
Pressure Relationships in Thoracic Cavity
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs...
Suctioning the Nasopharyngeal Airway
Equipment Required
Pulmonary Ventilation: Inhalation
Boyle's law becomes particularly pertinent when examining respiratory...
Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation...
Concept of Pressure at a Point
In a fluid at rest, pressure acts equally in...
Pulmonary Cycle: Exhalation