Joints

There are three types of fibrous joint:

• Suture (seam)
• A joint with a thin fibrous layer that binds skull bones
• Syndesomosis (band)
• Ligaments
• Gomphosis (bolt)
• A joint which consists of a peg and socket, such as the root of a tooth which is anchored into its socket by a fibrous ligament

There are two types of cartilaginous joint:

• Synchondrosis
• Hyaline cartilage as the connective tissue
• Eg epiphyseal plate between the epiphysis and diaphysis of bones
• Symphysis
• Fibrocartilage as the connective tissue
• Eg pubic symphysis

Synovial joints have articular surfaces covered with hyaline cartilage (shock absorption and lubrication), capsules to contain synovial fluid (limit excessive movement) and a synovial membrane which produces the fluid within it. There are 6 types of synovial joint:

• Saddle eg thumb
• Pivot eg neck
• Condyloid eg wrist
• Ball and socket eg shoulder or hip
• Hinge eg elbow or knee
• Gliding eg intercarpal

Functional classification works as follows:

• Synarthrosis permits little or no mobility – mostly fibrous joints eg skull sutures
• Amphiarthrosis permits slight mobility – mostly cartilaginous joints eg vertebrae
• Diarthrosis permits a variety of movements – mostly synovial eg shoulder, hip, elbow & knee