Agenesis of the mastoid antrum has surgical implications because failure to recognize its absence can result in disorientation during mastoid surgery, with potential to injure the lateral semicircular canal
and/ or the facial nerve.
An atticotomy is performed for wider exposure; if need be, an atticoantrotomy can be enlarged for a better view of the horizontal semicircular canal
The tumor had invaded the internal auditory canal below the superior semicircular canal
, and it extended anteriorly to the carotid artery.
The disadvantage of ENG is that it evaluates primarily the function of the lateral semicircular canals
8) This maneuver was designed to cause the free canaliths to migrate by gravitation from the posterior semicircular canal
to the utricle, where they would no longer interfere with the dynamics of the semicircular canals
3,4,17) Other semicircular canals
also may be affected, and more than one canal can be involved simultaneously.
Maximum stimulus is provided by a horizontal oscillation of the chair as the patient's head is tilted forward to bring the plane of the horizontal semicircular canal
to a right angle to the axis of rotation.
The acceleratory reflexes, attributed to the semicircular canals
, assist in tilt detection and sway displacement.
In the inner ear of vertebrates, the balance system consists of three semicircular canals
that contain fluid and sensory hair cells that detect movement of the head.
Although the pathophysiological process of the disease has not been fully clarified, currently, the widely accepted opinion is that the disease results from the accumulation of otoconia that are detached from the utricular macula in the semicircular canals
and thereby sensitizing such canals to gravity (1).
Head position definitely can have an effect on air sickness because it has to do with the orientation of the semicircular canals
in the inner ear," he told me.
In BPPV, degenerative debris dislocated from the utricle into the semicircular canals
increase the density of the cupula (1).