Flashcards in The Musculoskeletal System (review before bone disorders) Deck (37)
who is most likely to get arthritis?
1) elderly females
Majority of disorders of the musculoskeletal system are more likely to affect quality of life than be life threatening.
what is the effect of ageing on the Musculoskeletal System, in particular bones, joints and muscle?
1) Bones: Loss of bone mass occurs >30 years in both men and women
- Loss accelerates post-menopause in women
2) Joints: Joints stiffen with age as ligaments and tendons become more rigid
- Cartilage thins leading to increased friction/wear and tear
3) Muscle: Progressively lost from approx. 30yrs (sarcopenia), reduced mass and strength increases risk of injury
what are the symptoms caused by musculoskeletal conditions?
2) Other symptoms of musculoskeletal disorders include swelling, inflammation, bruising, loss of movement etc
pain is the chief symptom of most musculoskeletal disorders. describe the different types of pain
1) Bone pain (trauma, infection, cancer) results in deep, penetrating or dull pain
2) Muscle pain (trauma, inflammation, cramp/spasm etc)
3) Other joint and tendon/ligament pain- stiff, dull ache, less intense than bone pain, worse when moved or stretched.
- Where pain is felt might be misleading
how are musculoskeletal conditions diagnosed?
1) Observation of gait/movement of patient
2) Questions? Pain with movement, at rest, at night, any trauma?
3) Physical examination (swelling, bruising, tenderness, heat)
4) Blood tests (Biomarkers, inflammatory markers), X-ray, computed tomography (CT) scans etc
outline the Multiple functions of bone
1) Support - Framework for attachment of muscles etc
2) Protection - Protects internal organs from injury
3) Movement - Enable body movement by acting as levers and points of attachment for muscles
4) Mineral storage - Reservoir for calcium and phosphorus
5) Haematopoiesis - Certain bones house bone marrow which is essential for the production of blood cells etc
6) Energy storage - Certain bones contain fats/lipids (yellow marrow)
bones are Compact and Spongy. what are the compact part made of?
Compact/Cortical bone: Hard, dense outer layer of bone consisting of
1) Proteins (collagen (95%), proteoglycans etc) make up 33% of bone mass
2) Hydroxyapatite (mostly calcium phosphate) makes up 66% of bone mass
how does the microscopic structure of spongy bone differ from compact bone?
1) Less organized than compact bone (no osteons).
2) Trabeculae align along positions of stress and exhibit extensive cross-bracing.
3) Low density and strength (honeycomb structure). High surface area
what is Bone remodelling and when does it occur?
1) Bone remodelling- the formation of new bone to replace old bone
2) Occurs constantly in growing children to allow for lengthening and/or thickening of bones
3) Occurs in adults in response to:
- trauma (fractures) , stress (i.e. weight bearing exercise), Metabolic changes (use or replenishment of calcium stores)
name the bone cell types involved in remodelling?
what is the role of Osteoblasts?
1) Form new bone (”Blasts Build Bone”)
2) Synthesise and secrete collagen and other organic components of bone matrix
3) Initiate calcification
4) Located in bone membranes (i.e.periosteum and endosteum)
what is the role of Osteocytes?
1) formed when an osteoblast becomes embedded in the material it has secreted.
2) Connected to other osteocytes and the bone surface via canaliculi
3) Role to maintain bone, not by synthesising new bone, but by regulating mineral ion exchange
4) when osteocyte dies, surrounding bone dies
what is the role of Osteoclasts?
1) Remove deteriorating bone or unnecessary new bone (”Clasts Chew Bone”)
2) Large multi-nucleated cells
3) Secrete hydrogen ions to dissolve mineral matrix and hydrolytic enzymes (i.e. collagenase) to degrade other components of bone.
what is the origin of Osteoclasts and Osteoblast cells?
1) Osteoblast come from mesenchymal stem cells
2) Osteoclasts come from hematopoietic precursors
what happen when the quantity of Osteoclasts and Osteoblast is balanced? what happens when there is an imbalance?
1) healthy bone
2) if Osteoclast activity outweigh Osteoblast this leads to excessive loss of bone
3) if Osteoblast activity outweight Osteoclast this leads to formation of too much bone
- e.g. osteoporosis ( accelerated loss) Paget’s disease, Osteomalacia
what is a fracture and what is the most common cause?
1) A break in a bone, commonly associated with injury surrounding tissues
2) Trauma is the most common cause of fractures, although underlying conditions (I.e. osteoporosis, infections or bone tumours) can weaken bones and make them more likely to occur
what are the symptoms experienced when you have a fracture?
2) Loss of function
4) Crepitus (grating, popping, cracking)
5) Bleeding can occur from bone or surrounding tissues
what are the 4 stages that occur when you get a fracture?
1) Inflammatory phase
2) Inflam./Repair phase
3) Repair Phase
what happens in the Inflammatory phase of fracture repair?
1) Haematoma formation:
- Fracture disrupts blood vessels that supply bone and causes extensive bleeding
- A clot forms (haematoma)
- Lack of blood supply might lead to bone death
- Area is painful, swollen, inflamed and often bruised
what happens in the Inflam./Repair phase of fracture repair?
1) Granulation tissue forms
2) Debris is cleared by macrophages
3) Revascularisation occurs
4) Fibroblasts produce collagen that spans break
5) Chrondroblasts begin to secrete cartilage matrix
6) Osteoblasts begin to form spongy bone
what happens in the repair phase of fracture repair?
Bony Callus Formation:
1) Bone trabeculae increase in number
2) Fibrocartaginous callus is converted into bony callus of spongey bone
3) Typically takes 6-8 weeks
what happens in the remodeling phase of fracture repair?
Bone remodeling (months):
1) Bony callus is continually remodelled
2) Bone structure is restored
- Osteoclasts remove temporary supportive structures
- Osteoblasts rebuild compact bone
outline the treatment for a fracture
1) Immediate emergency treatment required
- Immobilise and support limb, elevate, ice
- Pain relief - not NSAIDs (reports of delayed healing)
- Open fractures need immediate treatment to clean and close wound. - Closed fractures less urgent
2) Further treatment required
- Immobilisation with casts or traction
- Surgical fixation of fracture (rods, plates, hip replacement)
what advice should be given to those with a cast?
1) Keep it dry
2) Never relieve itch with sharp or pointed objects
3) Check skin visible edge of cast for smell, redness or sores
4) Rest with care to prevent cast chaffing or digging into skin, pad rough edges
5) Elevate cast regularly to reduce risk of swelling
one complication of fractures is Compartment Syndrome. what is Compartment Syndrome, what are the symptoms and what is the treatment?
1) serious limb threatening condition caused by excessive swelling of injured muscles
2) Fibrous membrane surrounding muscle prevents expansion of swollen muscle and pressure builds within muscle
3) Pressure in muscle restricts blood flow and this leads to hypoxia, further injury of muscle and even muscle death
4) Symptoms: increasing pain in immobilised limb after fracture
5) Emergency medical treatment required!- Surgery to relieve pressure in constricted tissue.
another complication of fractures is a Pulmonary embolism. what is a Pulmonary embolism, what are the symptoms and what is the treatment?
1) Sudden blockage of artery in lung by blood clot
2) Common fatal complication after serious hip and pelvic fractures, less commonly in lower leg fractures and v. rarely in fractures of upper body
3) Risk increased due to combination of trauma to leg, forced immobility and reduced blood flow in veins due to swelling
4) Symptoms: chest pain, cough, shortness of breath
Emergency medical treatment required!
-heparin, warfarin etc can be given to reduce the occurrence of blood clots
joints are Junction between 2 or more bones. list some of the components that make up joints
Consist of components that ensure stability and reduce risk of damage:
1) Articular cartilage
2) Synovial fluid and membrane
3) Stabilising ligaments
Knee joints contain the following additional features. list the role of these features:
1) Meniscus, a cushion of cartilage that ensures even distribution of body weight in the joint
2) Bursa, a fluid filled sac that cushions bone and tendon
3) Patella, protection of joint
4) Ligaments- provide stability while allowing range of movement
Outline the function of Ligaments
1) Tough fibrous cords of connective tissue (collagen and elastin fibres) that stabilise and strengthen joints
2) Connect one bone to another
3) Do allow some stretch but only allow movement of joints in permitted direction.