• An abnormal bony growth in the middle ear that causes hearing loss.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• Formation of spongy bone in the labyrinth capsule which can progress toward the STAPES (stapedial fixation) or anteriorly toward the COCHLEA leading to conductive, sensorineural, or mixed HEARING LOSS. Several genes are associated with familial otosclerosis with varied clinical signs.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• In otosclerosis, a callus of bone accumulates on the stapes creating a partial fixation. This limits the movement of the stapes bone, which results in hearing loss.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• Pathological condition of the bony labyrinth of the ear, in which there is formation of spongy bone; may cause bony ankylosis of the stapes, resulting in conductive hearing loss; cochlear otosclerosis may also develop, resulting in sensorineural hearing loss.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Otosclerosis is a disease of the bone of the otic capsule that causes an abnormal accumulation of new bone within the oval window.
  Merck Manuals
  Merck & Co., Inc., 2025
• Ankylosis of the stapes was first described by Valsalva in 1704. Toynbee described fixation of the stapes to the margins of the oval window in 1841 and found similar cases in 136 of 1,000 temporal bone dissections.
  Medscape
  WebMD, 2025
• Otosclerosis, ear disorder characterized by abnormal bone growth in the middle ear, typically affecting the stapes (stirrup), a bone in the region of the oval window. It is at the oval window that the footplate of the stapes comes into contact with the fluids of the inner ear and acts as a piston...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025