Posted by Joe Rongo on Fri, Aug 14, 2009 @ 01:00 PM
Arthrology: Joints and Articulations... A joint or articulation is a point of contact between two or more bones.
When classifying anything in anatomy and physiology, we can look at two aspects: Function and Structure.
So it comes as no surprise that joints are classified functionally and structurally.
FUNCTIONAL: Looks at the move ability of the joint.
1. SYNARTROSES: immovable joints
2. AMPHIARTHROSES: slightly movable joints
3. DIARTHROSES: freely movable joints
Structural: Looks at how they are made, the building blocks.
1. FIBROUS: Have no joint cavity, and the bones are held together by a thin layer of fibrous tissue.
a. Suture - articulating bones separated by a thin layer of fibrous tissue.
Movement: Slightly (amphiarthrotic)
b. Syndesmosis - articulating bones united by dense fibrous tissue. Ex: Distal ends of the tibia and fibula.
Movement: Slight (amphiarthrotic)
c. Gomphosis
- a cone shaped peg that fits into a socket; articulating bones
separated by periodontal ligament. Ex: Roots of teeth in the alveolar
processes.
Movement: Slightly (amphiarthrotic)
2. CARTILAGINOUS: Has no joint cavity, and the articulating bones united by cartilage.
a. Synchondrosis
- Connecting material is hyaline cartilage. Ex: Temporary joint
between the diaphysis and epiphyses of a long bone. These are our
growth plates.
Movement: None (synarthrotic)
b. Symphysis - Connecting material is a broad, flat disc of fibrocartilage.
Movement: Slight (amphiarthrotic)
3. SYNOVIAL: These have a joint cavity, filled with
synovial fluid, and articular cartilage present, and the articular
capsule is composed of an outer fibrous capsule and an inner synovial
membrane. May contain necessary ligaments, articular discs (menisci),
and bursea.
Movement: Freely movable (diarthrotic) These are the only free moving
joints in the body, and are the joints associated with movement.