A fairly rigid joint between two or more hard elements, such as the bony plates of the skull.
A suture is a type of fibrous joint (or synarthrosis) that only occurs
in the skull. The bones are bound together by Sharpey’s fibers, a matrix of
connective tissue which provide a firm joint.
A small amount of movement is
permitted through these sutures that contributes to the compliance and
elasticity of the skull. The joint between the mandible and
the cranium, known as the temporomandibular joint, forms the only non-sutured
joint in the skull. Most sutures are named for the bones that they articulate.
At birth, many of the bones of the skull remain
unfused to the soft spots described as fontanelle. The bones fuse
relatively rapidly through a process known as craniosynotosis, although the
relative positions of the bones can continue to change through life. In old age
the cranial sutures may ossify completely, reducing the amount of elasticity
present in the skull. As such, the degree of ossification can be a useful tool in determining age postmortem.