The vestibule of the inner ear senses head motion for spatial orientation and bodily balance. In vertebrates, the vestibular system consists of three fluid filled semicircular canals, which detect rotational acceleration, and two gravity receptor organs, the utricle and saccule, which respond to linear acceleration and gravity (Figure 1). The utricle and saccule are also referred to as the otolithic organs because they contain bio-crystals called otoconia (otolith in fish). These crystals are partially embedded in a honeycomb layer atop a fibrous meshwork, which are the otoconial complex altogether. This complex rests on the stereociliary bundles of hair cells in the utricular and saccular sensory epithelium (aka.
