Endolymph is the fluid found in the membranous labyrinth of the inner ear. It is biochemically specialized and distinct from other central nervous system fluids, such as perilymph and cerebral spinal fluid. The major cation in endolymph is potassium, with a high concentration of positively charged ions, resulting in a high positive potential relative to other nearby fluids such as perilymph. This unique composition allows endolymph to play a crucial role in the sensation and transmission of balance, hearing, and position information
. The endolymph is involved in conveying position and balance to central sensory neural structures, and its disorders can lead to symptoms such as hearing loss and vertigo attacks
