Joint: Definition and What It Is

Medically and clinically reviewed by Jonathan Lee, MD and Dylan Peterson, PT, DPT

Joint Definition and Meaning

A joint is a connection between two or more bones in the body that provides stability and allows for various types of movement. In anatomical terms, a joint is a structure that connects bones. Joints have different configurations and functionalities, depending on where they’re located in the body. This can range from joints that permit wide ranges of motion, like the shoulder joint, to those that are mostly rigid, like the joints in the back of the foot. Joints are usually made up of cartilage, ligaments, tendons, and other soft tissues that provide both stability and mobility to the entire skeletal system.

Joint Types

There are several types of joints in the human body, mainly categorized into three groups based on their structure and function:

  • Synovial Joints: These joints are the most common and the most mobile. There are six types of synovial joints, which include hinge joints (like at the knee and elbow), ball-and-socket joints (like at the shoulder and hip) and pivot joints (like at the neck). These joints contain a special fluid that lubricates the joint, allowing for smooth movement.

  • Cartilaginous Joints: These joints are connected entirely by cartilage and allow limited movement, like the joint between the ribs and the sternum.

  • Fibrous Joints: These are mostly immovable joints connected by fibrous tissue. For instance, the bones in the skull are held together by fibrous joints known as sutures.

Joint Health: A Hinge Health Perspective

Our joints work hard all throughout the body, in ways both big and small. From the joints at the elbow that make sure your tennis swing is fluid to the ones that connect your thumb to your hand for easy texting, our joints are critical to our ability to engage in activities we enjoy. As a result, maintaining joint health through regular exercise and a nutritious diet is critical for overall well-being. 

Still, sometimes our joints — despite how strong and resilient they are — can get hurt as a result of injury or changes to your bones or connective tissues. Arthritis, which is characterized by inflammation or swelling in the joints, can cause pain. Tendinitis (tendonitis), which results from inflammation in tendons that connect muscles to bones, can impact joint mobility. Other conditions, like bursitis and osteoporosis, can also impact joint health.  No matter what the cause, changes in joint mobility can be frustrating, but there’s a lot you can do to help improve it. And that usually starts with moving more. Although moving when you have joint pain can be scary and uncomfortable, small changes to your habits can yield huge benefits. 

Exercises and stretches that focus on the affected joint (along with the muscles and connective tissues that support it) can help because they’re designed to improve mobility and function.

Exercises for Joint Health

Regular exercise is crucial for maintaining healthy joints. Weight-bearing exercises like walking or jogging can improve bone density, while strength training can build the muscles that support joints. Low-impact exercises such as swimming or cycling can provide a cardio boost with less strain on joints, until you’re able to gradually work up to higher-impact activities. Flexibility exercises like stretching and yoga can improve range of motion and alleviate joint stiffness.

Role of Physical Therapists in Joint Health

Physical therapists (PTs) play an essential role in promoting joint health, especially for individuals recovering from injuries or those with chronic joint issues like arthritis. PTs can provide an exercise regimen tailored to individual needs, focusing on improving mobility, strength, and function. You can see a physical therapist in person or use a program like Hinge Health to access a PT via telehealth/video visit.

How Hinge Health Can Help You 

If you have joint or muscle pain that makes it hard to move, you can get the relief you’ve been looking for with Hinge Health’s online exercise therapy program.

The best part: You don’t have to leave your home because our program is digital. That means you can easily get the care you need through our app, when and where it works for you. 

Through our program, you’ll have access to therapeutic exercises and stretches for your condition. 

Additionally, you’ll have a personal care team to guide, support, and tailor our program to you. See if you qualify for Hinge Health and confirm free coverage through your employer or benefit plan here.

This article and its contents are provided for educational and informational purposes only and do not constitute medical advice or professional services specific to you or your medical condition.


  1. Healthy Joints Matter. (2023, May). National Institute of Arthritis and Musculoskeletal and Skin Diseases. 

  2. Exercise and Bone Health. (2020, July). American Academy of Orthopaedic Surgeons.

  3. Rosen, H. N. (2023, February). Patient education: Osteoporosis prevention and treatment (Beyond the Basics). UpToDate. 

  4. Arthritis Types. (2019, February). CDC.

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