Endolymphatic Sac Cases

The mastoid cavity has been opened with a high-speed drill using both cutting and diamond burrs.  The white arrow indicates the balance canals of the inner ear. This solid bone houses the neural elements that make up our balance organ.  The black arrow indicates the sigmoid sinus—this is a continuation of the jugular vein from the neck into the intracranial cavity.  The bone overlying this vein is removed during endolymphatic sac surgery.

The white arrow once again indicates the sigmoid sinus in the mastoid cavity.  The black arrow is pointing towards the endolymphatic sac.  The bone overlying this sac has been removed to decompress the sac that holds the fluid of the inner ear.