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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Symptoms of Wrist Fracture

Breaking one or more bones of the wrist can cause a wrist fracture. A broken wrist occurs when people try to catch themselves during a fall and land hard on an outstretched hand. If you participate in sports like cricket or kabaddi, you may be at higher risk of a broken wrist. Also, if you have a condition in which bones such as osteoporosis where bones become thinner and more fragile, the chances of wrist fracture are high.

For bones to heal in proper alignment, it’s important to treat a broken wrist as soon as possible.  The delay in this might affect your ability to do everyday activities, such as writing, buttoning a shirt or knotting shoelaces. Also, early treatment helps in minimizing pain and stiffness. Thus one has to know the primary symptoms of wrist fracture so that the person can rush to the doctor.

Following are the symptoms of the broken wrist

  • Swelling
  • Severe pain while gripping or squeezing or moving hand or wrist
  • Bruising
  • Tenderness
  • Obvious deformity, such as a bent wrist

When to call a doctor

Looking at these symptoms, if you think you might have a broken wrist see a doctor immediately. If you’re having numbness, swelling or trouble moving your fingers you should rush to the doctor. A delay in diagnosis and treatment can lead to poor healing, restricts the motion and decreased grip strength.

This is the general information about Wrist Fracture. We recommend you to take your doctor’s advice for proper guidance. We hope this information adds value to your knowledge. Watch out this space for more such information. Greetings for SYS Medtech International PVT. LTD.

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Causes of distal radius fracture

If a person gets hit or slips, he first puts his hands on the ground to balance himself. This often causes great strain on the wrist and can lead to fractures. This problem can happen to people of any age, but it is more common in older and younger children particularly older women.

There are reasons why the distal radius fracture happens:

For children about ages 8 to 14, there is a period during which bones have grown longer because of growth spurts. But the bone mineral density has not yet caught up which leaves the newly-grown bones more vulnerable to fractures. Chances of fracture get increased, particularly during activities such as sports or play.

In the case of senior citizens, their hormone levels shift and bone mineral density starts to decrease. This is especially happening with women once they reach menopause. Their risk of a distal radius fracture begins to rise at age 50 and that risk doubles every 10 years. For men, the related risk is much later in their life, at the age of 80.

Falling onto a wrist is the most common cause of a distal radius fracture, people who actively participate in sports that involve potential falls, such as Kabaddi, Hockey, Football or Cricket, are also at greater risk for this injury.

Also, car accidents or similar traumatic events can also cause a distal radius fracture. But the majority of these cases are the result of falls.

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