Bones & Joints Flashcards
What is a joint?
Union between two bones
What are the three main groups of joints?
Fibrous
Cartilaginous
Synovial
What are the three fibrous joints?
Sutures
Syndesmoses
Gomphoses
Where are sutures found?
Between skull bones
What is the function of fibrous joints?
Allow growth but not movement
What are the gaps in a foetal skull called?
Fontanelles
Why are the sutures wide in foetal skulls?
Allow movement of bones in head when passing through the birth canal
What are the three types of sutures?
Squamous
Serrated
Denticulate
What is a syndesmoses?
Two bones slightly apart, joined by an interosseous membrane
What type of collagen is present in the interosseous membrane?
Type I
What is an example of a syndesmoses?
Radius and ulna
What is a gomphoses?
Fibrous tissue arranged as the periodontal ligament of the tooth root in a jaw
What is the function of a gomphoses?
Shock absorbers
Prevent enamel breaking by allowing slight tooth movement
What are the cartilaginous joints called?
Symphyses
Synchondroses
What is a symphysis?
Partially moveable joint
Apposing surfaces covered by hyaline cartilage but are separated by intervening fibrocartilage
What is a synchondroses?
Solid plate of hyaline cartilage between apposing surfaces (epiphyseal plate)
What is the role of a synchondroses?
Provide an area for growth
What type of joint helps add length to the base of the skull (pharynx development)?
Spheno-occipital synchondrosis
What are the four typical features of a synovial joint?
Articulating surfaces covered in hyaline cartilage
Joint cavity
Joint capsule
Synovial membrane
What are two possible additional features of synovial joints?
Bursae
Disc
Why do synovial joints have hyaline cartilage instead of just bone?
Tough but deformable so adapts under pressure
What is the role of the joint cavity?
Separate ends of bones
What is the role of the joint capsule?
Surround joint (like a sleeve) and completely enclose it
What are the thickenings of the joint capsule called?
Ligaments
What makes up the joint capsule?
Bundles of collagen fibres
What does the synovial membrane line?
Joint capsule interior
NOT articular surfaces
How does the viscosity of synovial fluid change as speed of joint movement increases?
Decreases
What does a synovial joint disc do?
Separates joint cavity into 2 to increase range of movement
What are bursae?
Sacs filled with synovial fluid
Where do you find bursae?
Where structures moving relative to each other are in tight apposition
What kind of movement is gliding?
Two surfaces slide over each other
Any direction but small distance travelled
What are the two pairs of angular movements and what do they do?
Flexion - decreases angle at a joint; extension - increases angle at a joint
Abduction - move away from midline; adduction - move toward midline
What are the two opposing rotational movements and what do they do?
External/lateral - turn away from midline
Internal/medial - turn toward midline
Where do rotational movements occur?
Head
Arm from shoulder
What is pronation? What is the opposite movement?
Turn palm to face posteriorly
Supination
What is inversion? What is the opposite movement?
Turn plantar surface of foot medially
Eversion
What does uniaxial describe?
Joints with only one axis of rotation/movement
What does biaxial describe?
Joints with two axes of movement that are at right angles to each other
What does multiaxial describe?
Joints with more than two axes of movement
What does non-axial describe?
Smaller joints that can move in all directions
Describe the anatomy of the temporomandibular joint
Condyle of mandible fits into fossa in temporal bone
Fossa is surrounded by a bar of bone except anteriorly
Loose joint capsule with lateral ligament and 2 accessory ligaments
4 major pairs of muscles that move joint form a rotator cuff around it
