Stapes
Sensory (eye & ear)OrgansHeadLeft and right
View left in 3D View right in 3D
- What it is
- The "stirrup": the innermost and smallest ossicle. Its head receives the incus; two slender crura (anterior and posterior) run down to an oval footplate that sits in the oval window, held by the annular ligament.
- Function
- Pistons in the oval window, driving pressure waves into the perilymph of the inner ear.
- Size
- About 3.3 mm long; footplate 3 x 1.4 mm; weight 3 mg, the smallest bone in the body.
- Clinical note
- In otosclerosis new bone fixes the footplate, causing conductive hearing loss; a stapedectomy replaces it with a tiny piston prosthesis.