The area in the diagram in the red circle shows the thumb saddle joint. The image above shows the index finger pressing onto the thumb saddle joint.
The trapezium bone is shaped like a saddle in the area of the thumb saddle joint. This particular shape of the trapezium bone allows for great mobility in the thumb.
Caption: The diagram shows the common structure of a joint. The left shown image clearly shows the principle of a joint which is affected by osteoarthritis: the cartilage (red arrows) is only partially existent (kind of like an old tire with worn down profile).
But even long after the straining situation is over, the pain may continue to linger in an osteoarthritis-damaged joint. In a healthy joint the cartilage acts as a shock absorber or buffer.
The damaged cartilage no longer functions as shock absorber between the bones, it has no buffing capabilities. In isolated cases a badly healed fracture close to the joint may cause carpometacarpal osteoarthritis (arthrosis).
Most of the time however the condition is not the result of an accident, in fact genetic inheritance factors play an important role. The typical areas that are affected by arthritic changes are hip and knee joints as well as the spine.
Many times the metatarsophalangeal joint of the big toe can be affected with osteoarthritis. Poly arthritis (also called rheumatoid arthritis) at first glance is spelled very similar to polyarthrosis however both conditions differ fundamentally from each other.
The rheumatoid arthritis is a systemic autoimmune disease of the entire connective tissue which also affects the joints. However, if the condition exists for an extended period of time, the typical course of the disease will simplify the distinction between poly arthritis and polyarthrosis greatly.
Note: In concluding this informational paper I would like to encourage you to address all questions you may have in connection with the thumb saddle joint and rhizarthrosis with your attending physician as this document does not constitute a replacement to a personal examination or consultancy through your doctor. Most people don't give it much thought; however, the action of moving your arm in this manner would not be possible without specialized structures called synovial joints.
In this lesson, we'll explore the six types of synovial joints and discuss their functions. These joints are found throughout the body; however, some locations serve as better examples than others.
For instance, when you turn your head side-to-side, it's due to the rotary motion permissible in pivot joints. Next, let's focus on hinge joints, shown as letter B on the diagram.
These joints can be found between your upper and lower arm bones, otherwise called your elbow, as well as your ankles, fingers, toes, and knees. Twisting or overextending a hinge joint can result in injury.
If you've ever twisted your knee or rolled your ankle, it's likely that a hinge joint was forced to move in a manner it shouldn't have. In fact, it's the saddle joint that makes our thumbs opposable, a trait that allows us to firmly grasp objects with our hands.
Here is a picture highlighting the location and type of bones associated with plane joints in your wrist. These joints form where the head of one or more bones fits in an elliptical cavity of another.
Try twisting your wrist in a circular motion while feeling your lower arm. Shoulders and hips are two major examples of this type of joint.
If you refer to our image, illustrating the body's joints, you'll notice how the ball literally fits into the socket. Our upper leg bone, or femur, has a rounded head region, which represents the ball.
Once these are joined together, the joint provides a huge range of motion. If you've ever heard of someone having hip replacement surgery, it's likely centered on repairing this joint.
The saddle joint makes your thumb opposable, while the plane joints allow your small wrist bones to shift in relation to one another. Condyloid joints form the connection between your lower arm and wrist.
Pivot Hinge Saddle Plane Condyloid Ball-and-socketNeck and wrist Fingers and knees Thumb Small bones of wrists and ankles Wrist and lower arm Shoulders and hips Once you've finished studying this lesson, you could test your ability to name and provide examples of the six types of synovial joints. To aid in your understanding of the material, illustrations, examples, and a brief quiz will be included.
DetailsIdentifiers Latin articulation sellers TA98A03.0.00.048TA21560FMA75298 Anatomical terminology A saddle joint (seller joint, articulation by reciprocal reception) is a type of synovial joint in which the opposing surfaces are reciprocally concave and convex. The classification of joints can be done based on function and structure.
Joints are of three categories based on function: amphiarthroses, arthroses, and arthroses. Diarthrosis joints can move freely to different angles.
Condyloid joints: This type of joint is formed when an elliptical-shaped hollow of a bone fits a similar elliptical-shaped end of another bone. This joint is responsible for allowing angular movement through two axes.
This joint plays a role in angular movements with a great range. The movement allowed by this joint is like a hinge of a door.
Carpal bones of the hand are examples of this joint. These joints move freely, are classified from the functional point of view as arthrosis and are characterized by the presence of articular cartilage, this covers the surfaces of the bones of the joint, is a healing cartilage.
At a saddle joint, both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other (see Figure below). This joint provides the thumb the ability to move away from the palm of the hand along two planes.
This movement of the first carpometacarpal joint is what gives humans their distinctive “opposable” thumbs. These are joints that can move freely, which means they allow a lot of movement, such as elbows, knees and shoulders.
These joints provide a low friction environment that can withstand a large amount of wear. They are further divided into six groups, according to the type of movement that occurs in them, which is allowed by its structure.
The basic types are sliding (flat, arterial), hinge (ginglymus), pivot (conchoidal), condole, chair and ball and socket. In the arthrosis or synovial joints, the ends of the bones are covered by a thin layer of healing cartilage and no cartilaginous tissue connects the bones to each other, so they are free to move in relation to each other.
This joint capsule is formed by fibrous material and this capsule encloses the joint cavity, whose internal surface is lined with synovial material. Hinge (ginglymus): The surface of the bone is a convex cylinder that articulates with the shallow concave facet of another.
Examples are the elbow, knee, ankle and interphalangeal joints of the fingers. Pivot (conchoidal or trochaic): The cylindrical surface of the bone is articulated with a ring of bone and fibrous tissue over another to produce a movement of rotation around a longitudinal axis.
An example is the articulation between the proximal end (elbow) of the radius and the bones of the ulna of the forearm, which must rotate around each other, producing supination or pronation. In addition, the articulation of the atlas and the axis, the first two cervical vertebrae of the neck, called the atlantoaxial joint, is another example that turns the head to the right or to the left.
These condyloid or ellipsoid joints are biaxial and produce a variety of movements in different planes, such as flexion, extension, abduction, adduction, bypass or a combination, but are unable to produce rotation. These joints allow for flexion, extension, abduction, adduction and bypass.
At the junction of the knee, the large femur bone of the thigh connects with the tibia and fibula of the leg, as well as with the patella. The reason why the saltwater crocodile has the most powerful jaw is the amount of muscle and its position on the hinge.
Note that the area in front of the hinge is open, with many holes and grooves for muscle attachment. Enormous muscles populate this region and work in the synovial joint in a powerful way, slamming the jaw.
While a bite of a crocodile could easily break your arm, your jaws are also closed once they have bitten. The shape of your head and the way your muscles join do not allow you to open your mouth again.