Joints - Classification by Movement
Joints can be classified by how much movement they allow. * Synarthroses: Immovable joints. Specific examples of synarthroses are suture joints (the joints in the skull) and synchondroses (the type of joint found in growth plates). * Amphiarthroses: Slightly moveable joints. A specific example of an amphiarthrosis is a symphysis (such as the joint between two vertebrae). * Diarthroses: Freely moveable joints. Specific examples of diarthroses are typical synovial joints such as the shoulder and wrist. *
Fibrous Joints * Fibrous joints are connected only by fibrous ligaments. A ligament is dense connective tissue that connects bone to bone (as opposed to tendons, which connect muscles to bones). Ligaments are named based on their position or based on the bones they attach.

There are 3 distinct types of fibrous joints: 1. Suture Joints 2. Gomphoses 3. Syndesmoses

Cartilaginous Joints | The next broad classification of joints we will discuss are cartilaginous joints. Cartilaginous joints are joined by either hyaline cartilage or fibrocartilage. The cartilage of cartilaginous joints is avascular and anervous except at the margins. Hyaline cartilage is slippery and strong when compressed, but has little tensile strength (strength against being stretched). Fibrocartilage, on the other hand, is tough and strong both when compressed and when stretched (high tensile strength). There are two distinct types of cartilaginous joints: 1. Synchondroses 2. Symphyses Synovial JointsSynovial joints are the most common, most moveable and most complex type of joint. Thus, we will spend a little more time on this joint type. Essentially, all synovial joints are diarthroses (freely moveable) thereby giving us the flexibility to walk, throw a ball, write, etc.Synovial joints have a general structure that is characteristic of this joint type. All synovial joints have: 1. A joint cavity between the bones 2. A synovial membrane lining 3. Articular cartilage |

Synovial Joint Illustration

Synovial Joint Classification type | illustration | function | examples | Ball-and-Socket-Joint | | Distal bone can move around a center in an indefinite number of axes. Main movements are flexion-extension, adduction-abduction, axial rotation and circumduction. | hips, shoulders | Ellipsoid Joint | | Distal bone has an ovoid articular surface and is received into an elliptical cavity, wich makes it impossible for the bones to do axial rotation. So main movements here are flexion-extension, adduction-abduction and circumduction. | wrist | Hinge Joint | | Here the distal bone can move only in one plane, flexion and extension (forward and backward). | knee, elbow, fingers | Flat Joint | | The main movements are flexion-extension and rotation. | wrist | Saddle Joint | | The saddle joint consists of two opposing surfaces that are reciprocally concave-convex, which allows flexion, extension, adduction, abduction, and circumduction, but no axial rotation. | thumb | Pivot Joint | | A pivot joint´s movement is limited to rotation. | Atlas and Axis, proximal radioulnar articulation |

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