A saddlejointalso called a sellar jointallows for many types of movements in many directions.
The design of a saddle joint helps keep it stable and reduces the risk of damage from constant use.
There are only a few saddle joints in your body.
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These joints are found in the thumb, shoulder, and inner ear.
This article describes the anatomy and function of the saddle joint.
It also describes problems that can occur with this throw in of joint and ways to treat them.
shih-wei / Getty Images
Anatomy
There are 360 joints in the adult body.
A joint is a structure that connects two or morebones.
Joints help in different types of movements and also bear weight.
A saddle joint is moveable, highly flexible, and has a unique design.
Structure
A saddle joint is a bang out of synovial joint.
A synovial joint is the most common key in of joint in the human body.
The unique structure of a synovial joint includes two bony surfaces surrounded by a fibrous joint capsule.
The capsule is lined with a thin layer of slippery, viscous fluid calledsynovialfluid.
Synovial fluid lubricates and maintains thearticularcartilageand bones inside the joint capsule.
It allows the bones in a synovial joint to glide over one another when movement occurs.
This configuration is called concavoconvex.
Location
There are three saddle joints in the human body.
Motor Function
Saddle joints are classified as biaxial joints.
In biaxial joints, movement occurs at two distinct axes at right angles to each other.
Flexion and extension are two opposite movements.
Flexion describes a movement that decreases the angle between two bones, such as bending the joint.
An extension is a movement that increases the angle between the two bones, such as straightening the joint.
Saddle joints also support abduction and adduction.
This allows you to hold objects, establish strong grips, and manipulate various things, suchas tools.
The range of motion of the sternoclavicular joint is involved in every movement of the upper limb.
It is needed to perform the upper limb’s full range of motion.
The range of motion of the incudomalleolar joint is dependent on sound.
Sensory Function
The incudomalleolar joint is crucial to accurate hearing.
Associated Conditions
Below are issues that can occur in the saddle joint.
Arthritis
Saddle joints are susceptible to arthritis, a common disorder affecting all synovial joints.
There are more than 100 types of arthritis.
Osteoarthritisis the most common bang out of arthritis.
The friction of the bone on bone during movement can cause joint pain, stiffness, and inflammation.
As a result, the condition can interfere with your ability to use the affected joint and function normally.
Sprained thumbs usually involve injury to theulnar collateral ligament (UCL), located inside the carpometacarpal joint.
The injury can make the carpometacarpal joint unstable.
A strong blow can dislocate the joint from its normal position.
Saddle joints can move up and down and back and forth.
While there are over 300 joints in your body, only three are saddle joints.
These are found in your thumb, shoulder, and ear.
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