Anatomy - joints Flashcards
What are the three groups of joint classification?
- Fibrous (fixed) or synarthrodial joints e.g. joining skull plates or radius and ulna
- Cartilaginous (slightly moveable) or amphiarthrodial joints - joined using cartilage e.g. ribs, vertebrae
- Synovial (freely moveable) or diarthrodial joints
What are the types of synovial joint?
- Gliding e.g. carpels
- Hinge e.g. elbow
- Ball and socket e.g. shoulder
- Pivot
- Condyloid
- Saddle
What are the features of a synovial joint?
- Joint capsule
- Joint cavity enclosed by the joint capsule
- Synovial membrane lining the joint capsule
- Synovial fluid forming a film over joint surfaces
- Hyaline (articular) cartilage covering the joint surfaces
Characteristics/ structure/ attachment of joint capsule?
- Composed of dense fibrous material
- Connects directly to periosteum of bone
- Poorly vascularised
- Richly innervated with joint receptors
- Often reinforced with ligamentous and muscular structures crossing the joint
Position/ characteristic/ function of synovial membrane
- Lines the capsule
- Richly vascularised
- Produces synovial fluid
What are the functions of synovial fluid?
- Reduces friction between the capsule and the cartilage
- Cartilage on cartilage lubrication
- Provides nutrition for the articular cartilage
- Resists the loads that produce shear of the joint surfaces
What is the mechanism for providing hyaline cartilage with nutrition and why?
During motion the articular cartilage is compressed and some of its fluid content exuded.
When pressure is released fluid re-enters the pores of the cartilage (like a sponge).
The cartilage is not vascularised and this is therefore its only source of nutrition
What is the function of ligaments and what are they made from and how does this affect their function?
Stability of the joint
Made from bundles of collagen fibres woven with elastin fibres
Amount of elastin varies significantly and affects the stability vs mobility
What is the structure of bursae?
Where are they found?
Example?
Sacs of synovial membrane separated by a film of synovial fluid
Located where moving structures are in close proximity: tendon/bone, bone/skin, ligament/bone
Bursa of elbow joint
What are menisci?
Where are they found?
What is their function?
Pads of fibrocartilage
Inside some synovial joints or on the margins of their articular surfaces
- Increase the fit (congruency) of the joint surfaces 2. Shock absorbency 3. maintain stability of the joint 4. Direct synovial fluid to areas of greatest friction
What are labrum?
Where are they found?
What is their function?
Form of fibrocartilage
Found around the margin of the concave joint surface of shoulder and hip
- Increase the fit (congruency) of the joint 2. Help maintain stability 3. Provide an attachment for ligaments and the joint capsule
What does congruency mean with respect to joints?
Fit
What is arthrokinematics?
Description of movement of one joint surface in relation to another
What are the definitions of joint movement and what types of joint do each of these?
- Roll - one surface rolls on another e.g. ball and socket or hinge joints
- Spin - rotation e.g. pivot joints
- Sliding - gliding of one component over another e.g. saddle and plane joints
What cells is cartilage comprised of?
Chondrocytes
