Types of Synovial Joints: Anatomy & Examples

Last updated on March 4th, 2024 at 10:03 am

Do you know each and every movable joint in the human body are synovial joints? They are called synovial joint because is filled with synovial fluid which acts as lubricants. It is also interesting to know that there are 6 types of synovial joints in our body.

But our body also has numerous immovable joints which do not allow any movement.

In this article, we are concerned about the movable joints / synovial joints, we will see what are its types with figures and examples.

But, before we proceed it would be important to learn a broad classification of joint and then we will go to types of synovial joints.

Types of joints in human body

Whenever two or more bones meet they form a joint. The human body has broadly two types of joint, one is immovable joint and another is movable joint.

Movable /Synovial joints

Observe our body when we walk, run, jump, play sports, swim, it’s not hard to guess that all this action is due to the movement at our joint. These joints are movable joints and our body consists of more of these types of joints.

Immovable joints

However, there are other joints whose purpose is to maintain the structure of the body parts by not allowing movement, they are fixed and do not take part in any kind of movement. These are immovable joints.

Examples of immovable joints

The best example is the joint in our skull. Somewhat spherical in shape, our skull is actually formed by joining the pieces of bones. All the pieces join together as immovable joint and form a stable structure of the skull.

But again immovable joints can again be divided into

• Fibrous joint
• Cartilaginous joints

Joints in our skull is an example of a fibrous joint.

Suggested reading: Pump handle movement of ribs with animation

What are the types of synovial joints?

There are a total of 7 types of synovial joints in the human body. These joints allow movement which is why it is also known as movable joints.

Actually, the articulating surface of this type of joint is filled with a special lubricating fluid known as synovial fluid. This fluid provides lubrication to the joint and so it is also termed as. A typical synovial joint looks something like this.

Before we proceed, let us brush up the anatomy of synovial joint which will help us understanding the different types of synovial joint.

Anatomy of synovial joint

The articular surface of the movable joint and has a smooth lining called cartilage. Smooth cartilage allows friction-less movement and this smoothness is further enhanced by body lubricants. Our movable joints are also lubricated and filled with fluid known as synovial fluid and this is why we call this joint a synovial Joint.

Remember in our childhood days when we would grease our bicycle or apply lubrication oil for a smooth ride, a moment of the wheels. If the bicycle is left unused for a long period and we do not lubricate, it would crackle and the movement of the wheels would be not that smooth.

This exactly also happens when our joints all also become dried up of lubricants, the smooth articular surface becomes eroded producing a crackling sound from the knee when we walk. It also produces great pain during walking and this condition is known as arthritis.

Coming back to the topic, our movable joint can further be classified under 7 types.

Let us try to understand each type, their structure, what makes them different from each other, with examples.

1) Plane Synovial Joint

We call it a plane because the articular surface is more or less flat or plane. To understand this let us take our palm as to flat articular surface when we rub our Palm from each other the one palm is actually gliding over the other.

So the plane joint permits gliding movement. The examples of plane joint are intercarpal joints, intertarsal joints, joints between articular processes of vertebrae.

2) Hinge joint

In the Hing type of joints, the joint functions as a hinge. To understand the hinge joint look at the door of your home, they are fixed over the Hinges from the sides and also observe the laptops, where the screen is also attached with the body with Hinges.

Also, observe that the screen of the laptop or the door is movable but it only in a single plane. So a type of synovial joint, the hinge joint of our body also allows movement in a single plane and this is why we call it a hinge joint.

Examples of hing joint

Examples are elbow joints, ankle joints, interphalangeal joints.

3) Pivot joint

In these types of joints, the joint consists of a peg that is surrounded by a ring and it also permits movement in one plane around the vertical axis. Our body also has joints that imitates peg and ring and forms pivot joint.

Example of pivot joint

One of the examples is the upper radio-ulnar joint present at the elbow joint. There is a central bony peg that is surrounded by Osteo-ligamentous ring. Other examples are inferior radio-ulnar joint there present on the wrist joint, atlantoaxial joint.

4) Condylar joint

The fifth one under the types of synovial joints is condylar joint. The articular surface in the condylar joint consists of two distinct condyles that fit with each other. one is a convex surface which fits perfectly into the concave surface this structure is called condyles.

Example of condylar joint

One of the best examples of a condylar joint is our knee joints. Knee joints consist of two condyles forming a bicondylar joint. This joints also permits movement mainly in one plane around the transverse axis, but it also allows partial payment in another plane such as rotation on the vertical axis.

Another example is, joints on the Jaws.

5) Ellipsoid joint 

The ellipsoid joint also consists of a convex surface that fits into the concave surface. But the only that differentiate from condylar types of the joint is the concave and convex surface is made up of more than one bone.

Ellipsoid joint examples

The example of wrist joint will clear the idea of the ellipsoid joint. In wrist joint, the concave surface is combinedly formed by the radius and ulna that fits into the concave surface which is made up of carpal bones.

Other examples are metacarpophalangeal joints and atlantooccipital joint.

6) Saddle joint

Have you ever observed the shape of a horse saddle? It is somewhat reciprocally concavoconvex. The articular surface of a saddle joint is also concavoconvex. Movement in saddle joint is somewhat similar to the ellipsoid joint, in addition, there is also rotation around a third axis.

Example of saddle joint

The examples are carpometacarpal joint thermochemical joints and clan calcaneocuboid joint.

7) Ball and socket joints 

The last on the list of types of synovial joints is the most movable of all the types. As the name suggests the ball and socket joint consists of a ball that fits into the socket a cup-shaped socket. The spherical ball fits into the cup-shaped socket and that’s why it allows movement in almost all direction. It gives great freedom of movement.

Example of ball and socket joint

One of the best examples is our shoulder joint.

The head of the humerus has a perfectly spherical shape head that fits into the cup-shaped socket of the scapula. Since the socket of the scapula is very shallow it allows great freedom of movement around every direction.

They allow Movement in flexion, extension, abduction, adduction, rotation, elevation Other examples are hip joint and talocalcaneonavicular joint