Lecture Notes: Paired Otoconial Masses

I. Otoconial Masses and the Utriculus

  • There are two otoconial masses (one on each side) located in the utriculus.
  • One mass is oriented horizontally, the other vertically.
  • Both masses send the same message during linear acceleration.

II. Otoconial Mass Movement and Disambiguating Acceleration

  • During linear acceleration (e.g., moving forward), the otoconial mass lags behind due to inertia.
  • This lag is similar to an object hanging in a car that swings backward during forward acceleration.
  • Tilting the head backward produces the same pull on the otoconial mass as linear acceleration.

III. The Problem of Sensory Disambiguation

  • Pilots relying solely on vestibular input (without vision) can confuse tilting their head back with linear acceleration (forward motion).
  • This confusion can lead to spatial disorientation and accidents.

IV. Importance of Vision and Future Topics

  • Vision usually helps disambiguate these sensations.
  • The lecture will explore otoconial disorders in the next segment. Otoconial Disorders