joints – hexafu

Fibrous joints are a type of joint that connects bones with dense, fibrous connective tissue.

They are also known as synarthroses.

According to one classification system they are said to be uniaxial (having one degree of freedom).

Examples:

Sutures in the skull, Joints between the forearm bones (radius and ulna), and Connections between teeth and jawbone.

Function:

Fibrous joints provide strong, immobile connections between bones. They are essential for maintaining structural integrity and stability, especially in areas that experience high forces or impact.

There are three main types of fibrous joints:

Sutures: Found between the bones of the skull, these joints form a tight, interlocking fit.
Syndesmoses: Connect two parallel bones, such as the tibia and fibula in the lower leg.
Gomphoses: Hold teeth in their sockets in the jawbone.

Structure:

Fibrous joints lack a joint cavity and are directly connected by fibrous tissue, typically consisting of collagen.

Synovial joint:

There are three types of synovial joints in the human body (by structural classification)

There are 6 major types.

Condyloid joints, also known as ellipsoidal or bicondylar joints, are a type of synovial joint that allows for movement in two planes:

abduction/adduction

flexion

Examples:

Atlanto-occipital joint (connecting the skull to the first vertebra of the neck)

Elbow joint (humeroradial and humeroulnar joints)

Knuckles (metacarpophalangeal joints)

Radiocarpal joint (meeting of the forearm with the wrist)

They play a crucial role in enabling fine motor skills, such as:

gripping

writing

typing

They provide stability and flexibility while allowing for a wide range of movements in the hands and wrists

Hinge joints also known as a ginglymus joint, is a type of synovial joint that allows for movement in one plane only.

Examples:

elbow joint

finger joints

knee joint

toe joint

Function:

Hinge joints enable flexion and extension movements, similar to the motion of a door hinge.

They provide stability and support while allowing for a wide range of motion in one plane.

Structure:

Two bones with cylindrical or convex-concave surfaces that fit together

Ligaments that stabilize the joint

Synovial fluid that lubricates the joint

Pivot joint, also known as a trochoid joint, is a type of synovial joint that allows for rotational movement around a single axis.

Examples:

Atlanto-axial joint (between the first two vertebrae of the neck)
Proximal radioulnar joint (between the radius and ulna in the forearm)
Distal radioulnar joint (between the radius and ulna at the wrist)

Function:

Pivot joints enable rotational movements between bones. Examples include:

Neck: Turning the head side-to-side
Forearm: Pronation and supination (turning the palm up and down)
Wrist: Rotating the hand around the wrist

Structure:

One bone is cylindrical in shape and fits into a ring-like structure formed by the other bone or ligaments.
The ring structure provides stability and prevents excessive rotation.

Plane joints, also known as gliding joints, are a type of synovial joint that allows for smooth, back-and-forth movements between two or more bones.

Examples:

Acromioclavicular joint in the shoulder

Costovertebral joints between ribs and vertebrae.

Intercarpal joints in the wrist

Intertarsal joints in the ankle

—-> plane joints are those between the carpals of the wrist

Function:

Plane joints provide stability and allow for limited gliding movements in multiple directions within the same plane. They enable movements such as:

Sliding

Gliding

Shifting

Importance:

Plane joints are essential for maintaining flexibility and range of motion in various body parts, especially in the hands

feet

spine

They allow for fine motor control and facilitate activities like grasping, walking, and running

Structure:

Flat or slightly curved articular surfaces, Thin layer of cartilage covering the surfaces, and Joint capsule containing synovial fluid.

Saddle joint (aka sellar joint) is a type of synovial joint that allows for a wide range of movement in two planes, but does not allow rotation.

The name comes from the shape of the joint, which resembles a saddle seat, with one bone shaped like a saddle and the other bone resting on top.

Saddle joints are important for many daily activities, such as grasping things and listening to music.

Examples:

Thumb: The carpometacarpal (CMC) joint at the base of the thumb allows the thumb to bend and touch the palm and fingers.
Shoulder: A saddle joint in the shoulder.
Ear: The incudomalleolar joint in the inner ear.
Acetabulofemoral joint (hip joint) – ball and socket joint.
Freely movable
Sits within articular capsule.
While there are over 300 joints in your body, only three are saddle joints.

etc

Cartilaginous joints – hold together by hyaline cartilage or fibrocartilage.

Tag: joints

anatomy – joints (1)

anatomy – joints