We've all heard the phrase "have you lost your mind?" but none of us would ever expect a regular check-up to confirm it.  That's exactly what happened to a 24 year-old woman in China.  When faced with dizziness and nausea, she decided to go to the doctor to perform a CAT scan and figure out what was wrong with her.  They soon realized that her entire cerebellum was missing from her head, and the space which should have contained the tissue was filled with cerebrospinal fluid instead.

Responsible for motor skills and speaking abilities, the cerebellum is located right under the left-right hemispheres of the main part of the brain and makes up only 10% of the total volume.  It also contains 50% of the brain's neurons, which is surprising since damage to these areas usually results in motor deficiency and speech impairment.  In the case of the young woman however, she is able to speak and walk with only minor defects.  

There are only nine other cases in which the cerebellum has been found missing and most of them were found through autopsies after the person had passed away.  With so many walking around with missing portions of the brain, this finding shows just how powerful and adaptable our brains can be.

Source: "Woman of 24 found to have no cerebellum in her brain"