What is the smallest bone in the human body?
General information only. This article explains the basics and is not medical advice. For anything about your own health, talk to a doctor or other qualified professional.
Quick answer
The stapes, in the middle ear, is the smallest bone in the human body. It’s only about 3 mm (0.1 inches) long, roughly the size of a grain of rice. Its name means “stirrup” in Latin because of its shape. It helps pass sound vibrations into the inner ear.
The three ear bones
The stapes is one of three tiny bones called the ossicles:
| Bone | Common name | Job |
|---|---|---|
| Malleus | Hammer | Attached to the eardrum |
| Incus | Anvil | Passes vibrations along |
| Stapes | Stirrup | Pushes vibrations into the fluid-filled inner ear |
How hearing works
- Sound waves enter the ear canal and make the eardrum vibrate.
- The three ossicles act like a lever, amplifying the vibrations about 20 times.
- The stapes presses on the oval window, a membrane leading to the inner ear.
- Fluid in the cochlea moves, bending tiny hair cells that send signals to the brain.
Bone records in the body
| Record | Bone |
|---|---|
| Smallest | Stapes (~3 mm) |
| Largest and strongest | Femur (thigh bone), about a quarter of your height |
| Only bone not connected to another bone | Hyoid, in the neck |
| Most bones in one area | Hands and feet together contain more than half of all bones |
How many bones do you have?
Adults have 206 bones. Babies are born with about 270–300, many of which fuse together as they grow, such as in the skull and lower spine.
Smallest muscle too
The stapedius, the muscle attached to the stapes, is the smallest skeletal muscle in the body. It tightens to protect the inner ear from very loud sounds.
For more about the body, see the largest internal organ and the strongest muscle.
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