Syndarthrodial Joints: Also called synarthroses or fibrous joints. Generally immovable joints that are found between bones that come into very close contact with each other and lack a synovial cavity. These bones are fastened tightly together by a fibrous connective tissue. See also diarthrodial jonits and amphiarthrodial joints.
There are three types of synarthrodial joints, syndesmosis, suture, and gomphosis:
- Syndesmosis - The bones are connected by long fibers of connective tissues forming a ligament known as an interosseous ligment, meaning in forms between bones. Since the ligament is somewhat flexible, it may permit some very slight degree of movement. An example is the tibiofibular joint which joins the distal ends of the tibia and fibula of the lower leg.
- Sutures - These occur only between the flat bones of the skull where the margins of the bones, which start out fairly broad, grow together and become connected by a thin fibrous layer called a sutural ligament. Before this, in an infant, the bones are incompletely developed and are separated by membraneous areas called fontanels, which allow the skull to change shape slightly during childbirth. During growth, these fontonels close and become sutures.
Some of these may, over time, become interlocked by a set of tiny bony processes, and eventually the sutural ligament can actually turn to bone itself, as in the lamboidal suture of the adult skull, which is found between the parietal and occipital bones.
Gomphosis - A conical process fits into a socket and is held in place by ligaments, as in the joining of a tooth in its alveolus (socket). The peglike root of the tooth is held in place by a peridontal ligament which surrounds the tooth and attaches it firmly to the jaw with thick collagenous fiber bundles.
This page created 22 Oct 2012 21:11
Last updated 18 Jul 2016 21:38