Sialolithiasis (sigh a lo THIGH a sis) is a condition where tiny salivary stones form in the glands. The stones, called sialoliths, are made of calcium. Some stones do not cause any symptoms, but some stones block the ducts. The saliva flow is partially or completely stopped.he three major salivary glands are the parotid gland, submandibular gland (also called the submaxillary gland), and sublingual glands. Saliva drains into the mouth through small tubes called ducts.
NASA facilities. NASA facilities exist across the United States, but also across the world. NASA Headquarters in Washington, DC provides overall guidance and political leadership to the agency. There are 10 NASA field centers, which provide leadership for and execution of NASA's work.
NASAâs Eyes. Welcome to NASAâs Eyes, a way for you to learn about your home planet, our solar system, the universe beyond and the spacecraft exploring them.Enjoy the experiences below on your mobile device, or visit this page on Mac or PC for even more ways to explore.ASAâs Eyes. Welcome to NASAâs Eyes, a way for you to learn about your home planet, our solar system, the universe beyond and the spacecraft exploring them.