Types of Human Joints (Featured Image)

Types of Joints in the Human Body – Anatomy

Overview:

A joint is defined as a connection between two bones in the skeleton. There are many ways in which joints can be classified.

They can be classified according to their structure, their mobility, and their range of motion.

Joint classification:

Structure

There are three distinct types-

  • Synovial joint
  • fibrous joint
  • Cartilaginous joints

Synovial jointFibrous JointCartilaginous joint

Synovial joint:

The synovial joint as it’s the most common joint found in the human body. Synovial joints have several characteristic features as a sagittal illustration of the knee joint.

First of all, synovial joints are surrounded by an articular capsule. This capsule consists of an outer fibrous layer that helps us to stabilize the joint and an inner synovial layer that absorbs and secretes synovial fluid lubricating the joints.

synovial joints 1

The articular surfaces of a synovial joint are covered in hyaline cartilage. This cartilage is also known as articular cartilage and acts to reduce friction and assists in shock absorption.

Additional structures may also be found within synovial joints such as articular discs.

We can see examples of these in the knee joint- the medial and lateral menisci.

medial and lateral menisci

The bursae, which are small sacs lined by the synovial membrane and filled with synovial fluid.

synovial fluid

The bursae act to reduce friction caused by muscles and tendons which are located over bony joints.

The synovial joints can be further sub-classified according to the shape of their articular surfaces and their range of motion.

These include,

  • Ball and socket joint
  • Hinge joint
  • Pivot joint
  • Condylar joint
  • Saddle joint
  • Plane joint

Fibrous joint:

In a fibrous joint, the bones are bound by a tough fibrous connective tissue. These joints exhibit little to no mobility.

fibrous joint

Types of fibrous joints:

  • Sutures
  • Gomphoses
  • Syndesmoses

 

The sutures, which are fibrous joints found exclusively between the bones of the skull.

This is the coronal suture. The suture connects the frontal bone to the parietal bones via suture ligaments.

Coronal suture

Gomphosis is found in the mouth, where the roots of the teeth articulate with the dental alveoli at the dentoalveolar joints.

dentoalveolar joints

The tooth is bound into its socket by the strong periodontal ligament.

periodontal ligament

The syndesmosis, which is formed by ligaments and a strong membrane that holds two bones in place. The interosseous membrane runs between the radius and ulna.

syndesmosissyndesmosis 1

Cartilaginous joint:

In a cartilaginous joint, the bones are connected by fibrocartilage or hyaline cartilage.

These joints can be subclassified into two types

  1. Synchondroses
  2. Symphyses

 

Synchondroses or primary cartilaginous joint, where the bones are connected by hyaline cartilage.

hyaline cartilage

This type of joint is found between the diaphysis and epiphysis of a growing long bone and will eventually become completely ossified in adulthood.

The second type of cartilaginous joint is known as a symphyses or secondary cartilaginous joint, where the bones are connected by fibrocartilage.

This type of joint is found primarily along the midline of the body; for example, the pubic symphysis.

pubic symphysis

Mobility:

Diarthrosis:

A diarthrosis is a freely mobile joint, and an example of this is the knee joint which is a synovial hinge joint. It’s worth noting that every synovial joint is a diarthrosis.

 

Amphiarthrosis:

An amphiarthrosis is a slightly mobile joint, and an example of this is the pubic symphysis. Which is a secondary cartilaginous joint.

The syndesmosis, which is a fibrous joint, is also an example of amphiarthrosis.

 

Synarthrosis:

 

A synarthrosis, which is an immobile joint, and an example of this is the coronal suture of the skull.

Other examples, of this type of joint include,

  • Gomphosis
  • Synchondrosis, which is a primary cartilaginous joint.

Range of Motion:

When classifying a joint based on its range of motion, it’s important to first understand the various axes of movement that the movements are occurring along in joint movement, there are three main axes

Axes of Movement:

There are three main axes,

  1. The sagittal axis, which passes horizontally from anterior to posterior.
  2. The frontal axis, which passes horizontally from left to right.
  3. The vertical axis, which passes vertically from superior to inferior.

Types:

  • The joint that can move back and forth along a single axis is called uniaxial. Examples of these are the hinge joint and the pivot joint.
  • Joints that move about two distinct axes are called biaxial. For example, the condylar joint and the saddle joint.
  • Joints that can move through all three axes are called polyaxial or multiaxial. The only example of this is the ball and socket joint.

Synovial Joints: Anatomy

Ball and socket joint:

ball and socket joint

The ball and socket joint, which is also known as the spheroid joint.  This is the only polyaxial joint and therefore, the most mobile of all joint types.

The movements that occur at these joints are,

  • Flexion and extension, which occur around a frontal axis.
  • Adduction and abduction, which occur around a sagittal axis.
  • Internal rotation and external rotation, which occur around a vertical axis.

Two examples of this joint are the acetabulofemoral joint or the hip joint and the glenohumeral joint, which is known as the shoulder joint.

Hinge joint:

Hinge joint

The hinge joint, which is only one axis of motion making it uniaxial.

The movements that occur at these joints are,

  • Flexion
  • Extension

Two examples of these joints are the tibiofemoral joint or the knee joint and the elbow joint.

So, we use our hinge joints when we show off to flex our biceps!

Pivot joint:

Pivot joint

Like the hinge joint, the pivot joint is also uniaxial. So, pivot joints, also known as rotary joints, allow movement around a single axis –this movement being rotation.

Condylar joint:

The condylar joint, which is also known as the ellipsoid joint. Condylar joints allow movement around two axes that are at right angles to each other. Therefore, they are described as biaxial joints.

An example of this joint is the radiocarpal joint or the wrist joint.

The movements that take place at this joint are,

  • Radial deviation and ulnar deviation, which occur around the sagittal axis.
  • Flexion and extension, which occur around the frontal axis.
  • These movements combine to produce circumduction of the wrist joint.

Saddle joint: 

Saddle Joint

Similar to the condylar joint, the saddle joint is a biaxial joint.

The movement that takes place at this joint is,

  • Abduction and Adduction
  • Flexion and Extension
  • Circumduction

An example of such a joint is the Carpometacarpal joint of the thumb.

Plane joint:

Plane joint

The plane joint is also known as the gliding joint. The plane joint performs a sliding or a gliding movement, where one bone moves across the surface of another.

An example of this joint is the acromioclavicular joint, which increases the flexibility of the shoulder.

 

For more information talk to a healthcare provider.

If you have any questions about Types of joints in Humans, please feel free and leave a comment.

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Types of Joints

6 Types Of Joints: Human Anatomy

The joints of the skeleton define the motion of the body and its limitations.

This article is about the types of joints in the human body.

Joints that are fibrous and cartilaginous hardly move, and some like the connection of the two pubic bones they don’t move at all.

fibrous and cartilaginous                pubic bone

 

Synovial Joints:

 

They have varying shapes, but the important thing about them is the movement they allow. Joints determine what position our bodies can take.

We learn them to invent poses. And we learn the limits to stretch the limits.

There are 6 types of synovial joints are Hinge, Pivot, Ball & socket, Ellipsoid, Saddle, and Plane.

 

6 Synovial joints

 

Let’s go through them one by one,

 

Hinge Joint:

 

The hinge is a very simple joint. It allows movement only on one axis. Its structure prevents rotation sideways.

The head of one bone wraps around the cylindrical head of the other, allowing a very stable rotation to the upper side.

 

Hinge Joint             

 

The hinge joint allows flexion and extension.

The best example of it is the elbow, it only does flexion and extension.

So, if the elbow only allows flexion and extension, how is it that we are able to twist the forearm?

Well, let’s take a look at the next joint.

 

Pivot Joint:

 

The pivot joint also allows rotation at only one axis. However, it rotates along the long axis.

 

 

Pivot joint Long axis

 

A cylindrical bone fits into a ring of bone and ligament, with the radioulnar joint just below the elbow.

 

Pivot joint

 

The cap on the radius bone fits nicely into this notch on the ulna bone.

 

Pivot joint (radioulnar)

Ligaments complete the ring, holding the bone in place and allow the radius only to rotate inside of it.

 

Pivot joint ring

 

The result on the forearm is what we call pronation and supination.

 

Pivot joint (Pronation)           Pivot joint (Supination)

 

During pronation, the base of the radius rotates over and around the head of the ulna. The ulna stays relatively still.

 

Pivot joint (Radius, Ulna)

 

Remember, the hinge joint at the elbow prevents the ulna from twisting. So all of that twisting happens at the radius.

And by the way, the distal joint of the ulna and radius is also a pivot joint.

The combination of the pivot at the top and at the bottom creates that twisting motion for pronation and supination.

 

Ball & Socket Joint:

 

The ball and socket is the champion of all joints. Its structure is just like how it sounds. A ball inside of a socket.

Ball and socket              Ball and socket 1

 

This simple and effective structure allows it to move in all axes- flexion/extension, abduction/adduction, rotation, and circumduction.

The two ball and socket joints of the body are at the hip and the shoulder.

 

Ball and socket (hip)                Ball and socket (Shoulder)

 

The hip has a deep socket, which gives it stability but limits some range of motion. The shoulder joints have a shallower socket, which gives it a greater range of motion but takes away some stability. Maybe that’s why a dislocated shoulder is so common.

 

Ellipsoid Joint:

 

Ellipsoid Joint

 

The ellipsoid joint is very similar to a ball and socket. However, the ligaments and their oval shape prevent rotation. But it still has the ability to rotate on two axes, which allows flexion/extension, abduction/adduction, and circumduction.

Circumduction is just a combination of all the others in a circular motion. The ball or oval head also slides inside the socket.

When it rotates along the wider plane, you can see how it pops out too much from the socket. So, it slides in back to the center.

A great example of an ellipsoid joint is the wrist, aka radiocarpal joint. The group of carpal bones rotates inside the socket of the radius.

 

Saddle Joint:

 

The saddle joint is similar to the ellipsoid but the rotation is limited mostly because of the bone structure. The structure of the saddle is very interesting.

 

              Saddle Joint 1

 

Both bones have a concave and convex surface. Convex means the surface sticks out, like a hill. Concave means the surface curves in, like a hole or a cave. The concave plane of one fits on the convex plane of the other.

 

Saddle Joint (Concave and convex)

 

So, this unique structure allows the joint to flex, extend, abduct, adduct, circumduction, and very slightly rotate.

An example of a saddle joint on the body is the carpometacarpal joint of the thumb.

 

Saddle Joint (Carpometacarpal Joint)

 

 

Plane Joint: 

 

It’s basically two flat surfaces, one on top of the other.

 

Plane Joint                Plane Joint

 

These surfaces can glide or rotate. They usually come in groups, like the carpal bone of the hand and the tarsal bone of the foot. The ligament holds these bones together but might allow some rotation and gliding.

 

Plane Joint

 

Another plane joint is the acromioclavicular joint. That’s the one between the clavicle and acromion process of the scapula.

 

Plane Joint

 

When we elevate the shoulder, the angle in here will adjust to keep the scapula vertical.

 

 

 

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