Bones & Joints Flashcards
Outline the mechanical properties of cartilage and bone
Bone = Protect body against mechanical damage, assist in movement, provides framework and shape, store minerals, produce RBCs/WBCs.
Cartilage = Reducing friction at joints, support resp tract, shock absorbers between weight-bearing bones, maintaining shape and flexibility of fleshy appendages.
Describe endochondral ossification
- Collar of periosteal bone appears in shaft,
- Nutrient arteries penetrate, supplying bone-depositing osteogenic cells – primary ossification centre formed,
- Medulla becomes cancellous bone, cartilage forms epiphyseal growth plates. Epiphyses develop secondary centres of ossification
- Epiphyses ossify, growth plates move apart lengthening bone,
- Epiphyseal growth plates replaced by bone. Hyaline articular cartilage persists
How many bones are in the body, vertebrae, upper and low limbs
206, 26 vertebral, 64 upper, 62 lower
How are bones classified by shape?
Flat bone (frontal skull),
sutural bone (skull),
irregular (vertebra),
long (femur)
sesamoid (patella),
short (carpal)
Outline the vasculature of bones
Nutrient artery supplies marrow through nutrient foreamen in middle of diaphysis, arteries in periosteum suppling outer 1/3 of cortex
some bones have a metaphyseal arteries that fuse with epiphyseal arteries in adulthood
What is avascular necrosis of bones?
Death of bone due to interruption of blood supply, most common cause = fracture/steroid use = collapse of necrotic segment + secondary osteoarthritis
Classify joints according to the tissues lying between the bones and describe the features of each type of joint
Fibrous = sutures of skull, radioulnar interosseous membrane.
Cartilaginous: primary = united by hyaline cartilage, secondary = articulated by hyaline with pad of fibrocartilage between.
Synovial = joint cavity containing synovial fluid, articulated by hyaline cartilage, fibrous capsule, synovial membrane that lines and prod synovial fluid.
What is Hiltons law?
The nerves supplying the joint capsule also supply the muscles moving the joint and the skin overlying the insertions of these muscles
Describe the factors contributing to stability of joints
Structure/shape, strength/tension of ligaments, tone of muscles, apposition of neighbouring soft tissues, hormones, use/disuse.
Classify synovial joints and describe the movements at these joints
Please Hand Peter, Crackers Sweets and Biscuits
Planar = flat articulating surface, sliding.
Hinge = pulley-shaped, uniaxial.
Pivot = rounded bone articulating within a ring, rotation.
Condyloid = oval condyle of one bone rests of elliptical cavity of another, flexion abduction adduction extension.
Saddle = one bone saddle shaped the other is the legs of rider, flexion extension adduction abduction.
Ball and socket = ball in a cup, flexion extension adduction abduction, ROTATION.
What is circumduction?
Combination of flexion extension adduction abduction
Outline the factors that limit movement at a joint
Arthritis = inflam/stiffness of joint. Osteoarthrosis = wearing away of articular surface, finally meaning bone on bone. Rheumatoid arthritis = autoimmune attack synovium.
Describe the structure and function of bursae
Sac lined with synovial membrane filled with synovial fluid = provides cushion, reduces friction
Describe the structure and function of tendon sheaths
Elongated burse, wrapped around tendon = reduce friction
Describe the effects of ageing on joints
Decreased prod of synovial fluid, thinning articular cartilage, shortening ligament and decreased flexibility, degenerative changes
Outline intramembranous ossification
- Mesenchymal stem cells –> osteoprogenitor cell –> osteoblasts,
- osteoblasts lay down osteoid (ECM: collagen I)
- osteoid calcifies forms spicules
- spicules form trabeculae which are replaced by lamellae of compact bone
