What are hinge joints? Anatomy and function

 Hinge joints function much like the hinge on a door, allowing bones to move in one direction back and forth with limited motion along other planes. The fingers, toes, elbows, knees, and ankles contain hinge joints.

Hinge joints are complex and contain many muscles and tissues. Osteoarthritis and trauma can cause pain and dysfunction in various parts of these joints.

In this article, we look at the anatomy and function of hinge joints. We also discuss the medical conditions and injuries that can affect these joints.

What are hinge joints?

Joints are places where bones meet. The body contains several different types of joint. Some joints have limited movements, such as those between the vertebrae, whereas others are more mobile, including the joints in the fingers and toes.

Hinge joints are those that allow movement along one plane. They facilitate bending and straightening actions, such as flexing a finger.

In a hinge joint, protective cartilage covers the bones, and a thick gel called synovial fluid lubricates them, allowing them to move without rubbing against one another. All hinge joints also contain muscles, ligaments, and other tissues that stabilize the joint.

Hinge joints are more stable than ball-and-socket joints, which include the shoulder and hip joints. However, ball-and-socket joints allow a greater range of movement along more than one plane.

The following body parts are hinge joints:

• elbow
• knee
• finger joints (interphalangeal joints)
• toe joints (interphalangeal joints)
• ankles (tibiotalar joint)

Below is a 3D model of a hinge joint which is fully interactive. Explore the model using your mouse pad or touchscreen to understand more about hinge joints.

Possible injuries

A range of injuries and medical conditions can affect hinge joints, including those below.

Osteoarthritis

As with other joints in the body, a person can develop osteoarthritis in a hinge joint. The hinge joints that osteoarthritis most commonlyTrusted Source affects are the knees, hands, and feet.

Stiff, painful joints are a hallmark of osteoarthritis. This stiffness develops when the protective cartilage that covers the bones in a joint breaks down, causing pain and swelling.

Factors that play a role in the development of osteoarthritis are:

• trauma
• activity level
• body weight
• lifestyle
• genetics

Dislocation

Although hinge joints are relatively stable, people can dislocate them. A dislocation occurs when a bone in the joint moves out of place. The most commonly dislocated hinge joints are those in the hands and feet.

However, certain sporting activities can increase a person’s risk of shoulder dislocation, while high energy trauma, such as that resulting from a car accident or high speed sporting injury, can lead to dislocation of the knee.

If a bone fracture also occurs, this is called a complex dislocation.

Tissue damage

Injuries that affect the muscles, ligaments, or other tissues in the joint can cause pain and inflammation in this area of the body.

Sporting injuries, especially those resulting from high impact activities, often affect hinge joints. Runner’s knee, for instance, can occur after repeated impact to the knee joint during running.

How to keep joints healthy

Experts are predicting rising ratesTrusted Source of arthritis in the United States due to an aging population. It is important that people try to keep the joints healthy as they get older.

People can help keep their joints healthy by:

• Moving them often: Exercising, stretching, and avoiding staying stationary for too long can all help keep the joints working well.
• Minimizing stress: When exercising, a person should pay attention to how the joints feel and avoid pushing their body too far. Excessive strain on the joints can erode the cartilage and cause lasting damage.
• Strengthening the muscles around the joints: Strong muscles will reduce the strain on joints, reducing the risk of injury, especially during sports.
• Maintaining a healthy weight: Carrying excess body weight places more strain on some joints, especially the knees. Reaching or maintaining a healthy weight can prevent this issue.

Some people use natural supplements, such as glucosamine or chondroitin, for joint health. Glucosamine and chondroitin are both present in cartilage and synovial fluid. Some people believe that taking glucosamine and chondroitin supplements can help preserve cartilage in the joints that osteoarthritis has affected.

In a 2017 studyTrusted Source, researchers analyzed the findings of different studies on the health benefits of glucosamine and chondroitin. They did not find convincing evidence that these supplements are an effective treatment for osteoarthritis.

The National Center for Complementary and Integrative HealthTrusted Source also report that the evidence to support the effectiveness of glucosamine and chondroitin is unclear. Researchers need to conduct more studies to determine the effects of these supplements.

There is no cure for osteoarthritis, but people can manage the condition using medication to slow down or prevent its progression. Medications can also relieve symptoms. Aerobic activity and strength training may help people with osteoarthritis who are dealing with pain and mobility issues.

Summary

Hinge joints allow the movement of certain parts of the body in one plane. There are hinge joints in the fingers, toes, knees, elbows, and ankles. Although hinge joints are stable, people can still dislocate a bone in them.

Osteoarthritis is common in hinge joints. People with osteoarthritis can try specific exercise programs that include aerobic and strength activities to help prevent the condition from worsening. Physical activity may also reduce osteoarthritis-related pain.

Source - Medical News Today