Joint Structure & Function Flashcards
What is a joint?
point of contact between two or more bones, cartilage and bones, or teeth and bones.
What is the study of joints
Arthrology
What are the 3 main types of joint?
fibrous
cartilaginous
synovial
What joints are solid and which are cavitated? (have a cavity)
Solid is fibrous and cartilaginous
Cavitated is synovial
What is an example of a fibrous joint?
Sutures of the skull
What is an example of a cartilaginous joint?
Pubic symphysis
Epiphyseal growth plate
Intervertebral disc
What are the bones held together by in a fibrous joint?
Articulating bones held together by fibrous connective tissue
How much movement occurs at a fibrous joint?
Little or no movement
What happens if the fibrous joint suture ossifies?
Synostosis - an ossified suture, immovable
What is a syndesmosis?
Syndesmosis - sheet of fibrous tissue (interosseous membrane) between bones
Where is a syndesmosis found?
Between radius and ulna or between tibia and fibula
What movement does the syndesmosis allow?
radius and ulna - allows pronation and supination
What holds your teeth in the mandible/maxilla socket?
Gomphosis - cone-shaped peg fits into a socket. e.g. teeth
How much do the cartilaginous joints move?
Little or no movement
What makes up a cartilaginous joint/how are bones attached?
Fibrocartilage (tough) or hyaline cartilage (smooth)
What is symphysis?
Cartilage joint in fibrous cartilage fibrocartilage
Where is symphysis found? and why?
Where we need more movement - pubic symphysis, IV discs
What is the syndchrondosis? Examples
Cartilage joint - hyaline cartilage, only present in childhood, at epiphyseal growth plate and costochondral joints
What are the costochondral joints?
Between ribs and sternum, syndchrondosis, hyaline cartilage, become more brittle with age
What are the majority of the joints in the body?
Synovial
How much can the synovial joints move?
Freely moveable but ranges between different joints
What is the fibrous capsule?
Holds synovial fluid in place, goes around the bone and joint
What lines the fibrous capsule?
Synovial membrane which makes the synovial fluid, made up of endothelial cells made up of GAG making fluid gloopy
Where is there loose connective tissue in a synovial joint?
Between the fibrous capsule and the synovial membrane, filled with blood vessels
What is the role of the articular cartilage?
Caps the ends of the bones forming the joint and gives smooth slippery surface to work with synovial fluid giving friction-less free movement
What is the articulating cartilage made up of?
Hyaline cartilage
What is an arthogram?
Iodine /contrast dye injected to see joint space and bursae
What is the ECM of hyaline cartilage made up of?
Deeper layer merges via a calcified layer with the subchondral bone.
80% water
Collagen type II
Proteoglycans
What do the properties of hyaline cartilage depend upon?
ECM composition
What is the function/properties of articulating cartilage?
Hyaline cartilage:
Smooth, slippery and very low coefficient of friction
Elastic, resilient structure that acts as a shock absorber to protect underlying bone
Is the hyaline cartilage calcified?
No apart from very deep layer which merges with the subchondral bone?
Why do joints appear as a gap on x-rays?
Black space is articular cartilage which is not seen on an x-ray
What else do some most synovial joints contain?
accessory ligaments and articular discs (menisci).
What do ligaments do?
Ligaments connect bone to bone
Help to stabilise and hold joint together
Joined to outer fibrous capsule
What do articular discs do?
Articular discs modify shape of joint surfaces
Help maintain stability of joint, and direct flow of synovial fluid to areas of greatest friction.
Where is the articular capsule?
surrounds joint. Encloses synovial cavity, uniting articulating bones.
What are the two layers of the articular capsule? What do they do?
Outer fibrous capsule (may contain ligaments).
Inner synovial membrane (secretes lubricating and joint nourishing synovial fluid).
What is the cause of osteoarthirits?
Loss of articulating cartilage
What are the 6 types of synovial joints?
Planar, Hinge, Pivot, Ellipsoidal, Saddle, Ball & Socket
What movements can planar joints do?
Gliding movements (side to side and back and forth)
Examples of planar joints
Intercarpals and intertarsals
How does a hinge joint form?
Convex surface of one bone fitting into concave surface of another bone
What movements are in a hinge joint?
Flexion and extension, single plane
Examples of a hinge joint?
elbow, knee, Interpharyngeal
Examples of a pivot joint
Proximal radio-ulnar joint (annular ligament)
Atlas rotating around the axis
How does a pivot joint form
Round/pointed surface of one bone fitting into a ring formed by another bone or ligament
What movement occurs at pivot joints?
Rotational, pronation and supination in proximal radio-ulnar
What is another name for the ellipsoidal joint?
Condyloid joint
How does a condyloid form?
condyle of one bone fits into cavity of another bone
What are the movements of the condyloid joint?
Flexion, extension, adduction, abduction, circumduction
What is an example of a condyloid joint?
Carpals and radius
Which joints are saddle joint?
Carpal-metacarpal of the thumb
carpal is trapezium
How does a saddle joint form?
Saddle shaped bone and other is rider
What movements can a saddle joint do?
Flexion-extension
Abduction-adduction
Circumduction
How does a ball and socket joint form?
Ball shaped surface of one bone fits into cup like depression of the other
What movements are in the ball and socket joint?
flexion, extension, adduction, abduction, circumduction
What are some examples of a ball and socket joint?
Shoulder and hip
