Joints Flashcards
Define a joint.
A joint is defined as a connection between two bones in the skeletal system.
How can joints be classified?
Joints can be classified by the type of the tissue present (fibrous, cartilaginous or synovial), or by the degree of movement permitted (synarthrosis, amphiarthrosis or diarthrosis).
what does synarthrosis mean?
joint is immobile
what does amphiarthrosis mean?
joint is slightly moveable
what does diarthrosis mean?
joint is freely moveable
Describe fibrous joints.
A fibrous joint is where the bones are bound by a tough, fibrous tissue. These are typically joints that require strength and stability over range of movement.
how can fibrous joints be further sub-divided?
Fibrous joints can be further sub-classified into sutures, gomphoses and syndesmoses.
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describe a cartilaginous joint and the two main subtypes
In a cartilaginous joint, the bones are united by fibrocartilage or hyaline cartilage.
There are two main types: synchondroses (primary cartilaginous) and symphyses (secondary cartilaginous).
describe synchondroses (primary cartilaginous) and give an example
In a synchondrosis, the bones are connected by hyaline cartilage. These joints are immovable (synarthrosis).
An example of a synchondrosis is the joint between the diaphysis and epiphysis of a growing long bone.
describe symphyses (secondary cartilaginous) and give a couple examples
Symphysial joints are where the bones are united by a layer of fibrocartilage. They are slightly movable (amphiarthrosis).
Examples include the pubic symphysis, and the joints between vertebral bodies.
describe a synovial joint
A synovial joint is defined by the presence of a fluid-filled joint cavity contained within a fibrous capsule.
They are freely movable (diarthrosis) and are the most common type of joint found in the body.
describe the movement allowed by synovial hinge joints and give examples
Hinge – permits movement in one plane – usually flexion and extension.
E.g. elbow joint, ankle joint, knee joint.
describe the movement allowed by synovial saddle joints and give examples
Saddle – named due to its resemblance to a saddle on a horse’s back. It is characterised by opposing articular surfaces with a reciprocal concave-convex shape.
E.g. carpometacarpal joints, sternoclavicular joints
describe the movement allowed by synovial plane joints and give examples
the articular surfaces are relatively flat, allowing the bones to glide over one another.
E.g. acromioclavicular joint, subtalar joint.
describe the movement allowed by synovial Pivot joints and give examples
allows for rotation only. It is formed by a central bony pivot, which is surrounded by a bony-ligamentous ring
E.g. proximal and distal radioulnar joints, atlantoaxial joint.
describe the movement allowed by synovial Condyloid joints and give examples
Condyloid – contains a convex surface which articulates with a concave elliptical cavity. They are also known as ellipsoid joints.
E.g. wrist joint, metacarpophalangeal joint, metatarsophalangeal joint.
describe the movement allowed by synovial ball and socket joints and give examples
Ball and Socket – where the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. It permits free movement in numerous axes.
E.g. hip joint, shoulder joint.
