Types of Pivot Joints
There is just one axis of rotation possible with a pivot joint. It is also known as the “monaxial joint”. In this joint, the rounded bone fits into a shallow depression in another bone and one bone rotates around another within a concave ring formed in the second bone. A ligament lines this ring to provide smooth motion. There are two major types of Pivot Joints- Radioulnar Joint and Atlas-axis joint. These are explained below:
Also Read: Difference between Ligament and Tendons
Proximal Radioulnar Joint
It is located near the elbow and is located within the same articular capsule. It is created by the articulation of the radial notch of the ulna and the head of the radius. The annular radial ligament, which surrounds the joint like a collar, secures the radial head like a cap. The synovial membrane, which lines this ligament, ensures that movement is fluid and free from excessive wear and tear. The movement allowed by these joints is; “Pronation” which is formed by the pronator quadratus and pronator teres, and another one is “Supination” which is formed by the supinator and biceps brachii.
Distal Radioulnar Joint
It is located just proximally to the wrist joint. It is created by the articulation between the ulnar notch of the radius, and the ulnar head. The articular disk, a fibrocartilaginous ligament, is present in the anterior and posterior ligament that support the joint and their function is to bind the radius and ulna together or separate the distal radioulnar joint from the wrist joint.
Median Atlantoaxial Joint
This joint lies between the two cervical vertebrae of the spine. The first vertebra is called atlas and the second one is called the Axis. It is located between first and second vertebra in the spine. It is created by the articulation between the odontoid process (dens) of the axis and the anterior arch of the atlas, and their function is to allow rotational movement of the head, particularly the ability to turn the head from side to side.
Pivot Joints: Definition, Diagram, & its Examples
Pivot joints are those joints that show movement in a single direction. Joints are points of contact between bones. The joint acts as a fulcrum that helps in dispersing the force generated by the muscles. The Pivot joint is a type of Synovial joint that is characterized by the presence of synovial fluid. Other types of Synovial joints are Ball and Socket Joints, Hinge Joints, and Gliding Joints. One example of the pivot joint is the joint between the atlas and the axis. Another Pivot joint in the human body is made of the bones in the wrist.
Table of Content
- What is a Pivot Joint?
- Types of Pivot Joints
- Pivot Joints Diagram
- Pivot Joints Examples
- Functions of Pivot Joints
- Implications of Pivot joints
- Disorders of Pivot Joints