Perilymphfilled

Perilymphfilled is a descriptive term used to denote anatomical spaces within the inner ear that are filled with perilymph fluid. In standard anatomy, these perilymph-filled spaces include the scala tympani and scala vestibuli of the cochlea, as well as the vestibule and the semicircular canals, which reside in the bony labyrinth surrounding the membranous labyrinth.

Perilymph, the fluid occupying these spaces, has an ionic composition similar to extracellular fluid, with relatively high sodium and low potassium compared with endolymph. This composition supports the mechanical function of the inner ear and helps maintain the environment surrounding the sensory hair cells within the membranous labyrinth.

Physiology and role: The perilymph-filled compartments transmit mechanical energy from sound-induced vibrations at the oval window through the cochlear partition and assist in maintaining pressure and fluid balance across the inner ear. By surrounding the endolymphatic space, perilymph helps buffer and stabilize the delicate pressure dynamics essential for hearing and balance.

Clinical considerations: Disruption of perilymph integrity, such as in a perilymph fistula from trauma or barotrauma, can lead to leakage into adjacent spaces and result in vertigo, hearing loss, or imbalance. Diagnosis relies on clinical evaluation, imaging, and audiological testing, while treatment ranges from observation to surgical repair depending on severity and etiology.

Etymology and usage: The term perilymphfilled is descriptive rather than naming a separate structure; it is used to characterize spaces that contain perilymph rather than endolymph.