2. Joints + fractures Flashcards
3 types of joints
1) Fibrous 2) Cartilaginous 3) Synovial
Fibrous joints
no joint cavity
no movement
3 sub-types of fibrous joints
1) Sutures of skull 2) Syndesmoses between tibia and fibula 3)Gomphoses of teeth + maxilla
Cartilaginous joints
- bone joins with Cartilage - Type I + Type II
Type I cartilaginous joint
hyaline cartilage only
never breaks
Type II Cartilaginous joint
-2 types of Cartilage: hyaline + Fibrocartilage
6 features of Synovial joints
1) bone ends covered in hyaline Cartilage 2) joint surrounded by capsule 3) within the capsule is a joint cavity 4) capsule reinforced outside by ligaments 5) cavity lined inside by synovial membrane 6) joint capable of varying degree of movements
Synovium
contains fibroblasts
secrete hyaluronic acid for lubrication
how many types of synovial joint
6
Joint stability is conferred by which 3 things ?
1) Joint shape 2) Ligaments 3) Tendons + muscles
Fracture
Break or crack in a bone
Osteoporosis
condition that weakens bones
more likely to break
Osteogenesis imperfecta
- group of genetic disorders - bones that break easily
Nightstick fracture
isolated fractures of the ulna
mid-diaphysis
direct blow
Monteggia fracture
fracture of proximal 3rd of ulna
dislocation of head of radius
indirect blow
Closed fracture
- no break in skin or protrusion of bone fragment
Open fracture
- skin broken, usually with fragment protruding
Buckle fracture
Greenstick fracture
Salter-Harris classification of growth plate injuries Mnemonic : SALTR
Type1: S= slipped 5-7% = through growth plate
Type 2: A = above 75% = through growth plate + metaphysis
Type 3: L = lower 7-10% = through growth plate + epiphysis
Type 4: T = through 10% = through metaphysis, growth plate + epiphysis
Type 5: R = ruined <1% = crushing type injury - growth plate not displaced but damaged by direct compression
Stress fracture
- very small sliver or crack in bone - x-rays don’t show any evidence of them - 2 types: fatigue fracture + insufficiency fracture
Fatigue fracture
- application of abnormal stress to bone with normal elastic resistance
Insufficiency fracture
- when normal stress is placed on a bone with deficient elastic resistance
Compression fracture
- most common in vertebrae - vertebral body compressed to a smaller height -occurs from trauma or osteoporosis
Colles fracture (dinner fork deformity)
fracture through distal metaphysis of radius
no further than 4cm proximal to distal articulate surface of radius
Avulsion fracture
- tendon or ligament pulls off a piece of the bone
hyaline cartilage
elastic cartilage
fibrocartilaginous cartilage
Fracture repair
- First aid stabilize the break with a splint
- Diagnosis via X-ray
- Returned to their natural positions manually (reduction). This is very painful without anesthesia.
3 major phases of fracture healing
- Reactive Phase
- Reparative Phase
- Remodeling Phase
Reactive phase of fracture healing
Short period of bleeding
hematoma (6-8 hours post injury)
No blood flow between the 2 broken bone ends
Cells in the fracture hematoma begin to die
inflammatory response + swelling occurs
Blood capillaries grow into fracture hematoma
Phagocytes & osteoclasts remove dead cells
Reparative Phase of fracture healing
proximal periosteal cells → chondroblasts →form hyaline cartilage
periosteal reaction
distal periosteal cells →osteoblasts → form woven bone
2 new tissues grow form a fracture callus
Remodeling Phase of fracture healing
Cancellous bones are replaced with compact bone in the cortex of the bone
Callus is removed
Fracture site is remodelled by osteoblasts and osteoclasts
plane joint
sliding movement only
pivot joint
1 plane rotation
saddle
2 planes of movement + controlled rotation
ellipsoid joint
2 planes
ball and socket joint
multiaxial in 3 planes
hinge joint
1 plane, sometimes rotation
most common fractures in people with osteoporosis
wrist
hip
vertebrae
