synarthrosis

A synarthrosis is an immovable joint where bones are united by fibrous connective tissue. These joints lack fluid and can be either transient (fusing after birth) or permanent.1234

Examples of synarthroses include:
* Fibrous joints: These have collagen fibers connecting the bones. Sutures in the adult skull and gomphoses (where teeth meet the jawbone) are examples.2
* Cartilaginous joints (synchondroses): These involve a cartilaginous stage before ossification and are typically transient, disappearing by age 25. Examples include joints within the skull that allow for bone growth.3