Types and Motions of Joints

 

By Rick Morris

 

If you've ever sprained an ankle or a knee during your distance run you know the importance of joints and what the joints do. Here are the basics of joints for distance runners.

 

There are six types of freely moveable joints, each of which has its own characteristics.

 

 

Immovable, slightly movable and freely movable joints.

 

Joints are divided into three categories according to their degree of motion. The three classifications are synarthrodial (immovable), amphiarthrodial (slightly movable) and diarthrodial (freely movable).

 

The only synarthrodial (immovable) joints in the body are where the bones of the cranium (skull) join and in the sockets of the teeth. Amphiarthrodial (slightly movable) joints are either held together by strong ligaments such as joints in your collarbone or that are separated by cartilage such as where your ribs attach to your sternum (breastbone).

 

For our purposes here we will concentrate only on the diarthrodial joints (freely movable). These are the only joints that are involved in muscular movements and motions.

 

There are six types of freely movable joints; arthrodial, condyloidal, enarthrodial, ginglymus, sellar and trochoidal.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Arthrodial

 

An arthrodial joint is a gliding joint. Two flat bony surfaces butt up against each other. The only motion permitted is a limited gliding motion. An example of this joint is the carpal bones in the wrist, which lie between the wrist joint and the fingers.

 

Condyloidal

 

This joint is a type of ball & socket joint that allow movement in one direction only. No rotary motions are possible in this type of joint.

 

Enarthrodial

 

This is the classic ball & socket joint. Movement is possible in all planes (directions). Rotary movements are also allowed. Examples of this type of joint are the shoulder and hip joints.

 

Ginglymus

 

The ginglymus joint is a hinge joint. This type of joint allows a wide range of motion in one direction only. Examples of this type of joint are the elbow and knee joints.

 

Sellar

 

This is another type of ball & socket joint. This joint allows movement in all planes, but does not allow rotation. An example of this joint is the thumb joint.

 

Trochoidal

 

This is a joint that is associated with long bones. The only motion allowed is rotational. An example is the rotation of the radius at the radioulnar joint. That is where the two bones of your lower arm are joined.

 

 

 

 

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