The Musculoskeletal System (review before bone disorders)

Question 1

who is most likely to get arthritis?

Answer 1

1) elderly females

Majority of disorders of the musculoskeletal system are more likely to affect quality of life than be life threatening.

Question 2

what is the effect of ageing on the Musculoskeletal System, in particular bones, joints and muscle?

Answer 2

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

Question 3

what are the symptoms caused by musculoskeletal conditions?

Answer 3

1) pain

2) Other symptoms of musculoskeletal disorders include swelling, inflammation, bruising, loss of movement etc

Question 4

pain is the chief symptom of most musculoskeletal disorders. describe the different types of pain

Answer 4

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

Question 5

how are musculoskeletal conditions diagnosed?

Answer 5

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

Question 6

outline the Multiple functions of bone

Answer 6

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)

Question 7

bones are Compact and Spongy. what are the compact part made of?

Answer 7

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

Question 8

how does the microscopic structure of spongy bone differ from compact bone?

Answer 8

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

Question 9

what is Bone remodelling and when does it occur?

Answer 9

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)

Question 10

name the bone cell types involved in remodelling?

Answer 10

1) Osteoblasts
2) Osteocytes
3) Osteoclasts

Question 11

what is the role of Osteoblasts?

Answer 11

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)

Question 12

what is the role of Osteocytes?

Answer 12

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

Question 13

what is the role of Osteoclasts?

Answer 13

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.

Question 14

what is the origin of Osteoclasts and Osteoblast cells?

Answer 14

1) Osteoblast come from mesenchymal stem cells

2) Osteoclasts come from hematopoietic precursors

Question 15

what happen when the quantity of Osteoclasts and Osteoblast is balanced? what happens when there is an imbalance?

Answer 15

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

Question 16

what is a fracture and what is the most common cause?

Answer 16

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

Question 17

what are the symptoms experienced when you have a fracture?

Answer 17

1) Pain
2) Loss of function
3) Deformity
4) Crepitus (grating, popping, cracking)
5) Bleeding can occur from bone or surrounding tissues

Question 18

what are the 4 stages that occur when you get a fracture?

Answer 18

1) Inflammatory phase
2) Inflam./Repair phase
3) Repair Phase
4) Remodeling

Question 19

what happens in the Inflammatory phase of fracture repair?

Answer 19

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

Question 20

what happens in the Inflam./Repair phase of fracture repair?

Answer 20

Callus formation:

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

Question 21

what happens in the repair phase of fracture repair?

Answer 21

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

Question 22

what happens in the remodeling phase of fracture repair?

Answer 22

Bone remodeling (months):

1) Bony callus is continually remodelled
2) Bone structure is restored
- Osteoclasts remove temporary supportive structures
- Osteoblasts rebuild compact bone

Question 23

outline the treatment for a fracture

Answer 23

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)

Question 24

what advice should be given to those with a cast?

Answer 24

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

Question 25

one complication of fractures is Compartment Syndrome. what is Compartment Syndrome, what are the symptoms and what is the treatment?

Answer 25

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.

Question 26

another complication of fractures is a Pulmonary embolism. what is a Pulmonary embolism, what are the symptoms and what is the treatment?

Answer 26

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

Question 27

joints are Junction between 2 or more bones. list some of the components that make up joints

Answer 27

Consist of components that ensure stability and reduce risk of damage:

1) Articular cartilage
2) Synovial fluid and membrane
3) Stabilising ligaments

Question 28

Knee joints contain the following additional features. list the role of these features:

1) Meniscus
2) Bursa
3) Patella
4) Ligaments

Answer 28

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

Question 29

Outline the function of Ligaments

Answer 29

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.

Question 30

outline the role of Tendons and Bursa

Answer 30

1) Tendons: Tough bands of connective tissue (made up mostly of collagen) that attach muscle to bone
2) Bursa- Fluid filled sacs that lie beneath tendon and protect it from injury
- Cushion tendon and adjacent structures from wear (i.e. bone and ligaments in knee).

Question 31

list the three types of muscle

Answer 31

Skeletal, Cardiac and Smooth muscle

Question 32

what is the function of Skeletal (Striated) Muscle?

Answer 32

1) Bundles of contractile fibres that are responsible for our movement and posture
2) Attached to bones and arranged in opposing groups
3) Opposing arrangement ensures smoothness of movement and limits risk of damage

Question 33

how does skeletal muscle grow and repair itself?

Answer 33

Satelite cells are myogenic stem cells that are responsible for the post-natal growth, repair and maintenance of skeletal muscle

Question 34

list some sporting injuries

Answer 34

1) Strains: Damaged/torn muscle
2 Sprains: Damaged/torn ligaments 
3) Tendinitis: Inflammation of tendon 
4) Stress fractures of foot
5) Shin splints: Fractures of shin bone

Question 35

How are sporting injuries treated?

Answer 35

RICE:

1) Rest: Minimises internal bleeding and swelling, prevents further injury
2) Ice: Reduces pain and inflammation, Ice for 60-90 minutes
3) Compression: reduced swelling, risk of further injury
4) Elevation: Reduce swelling

Question 36

outline the 3 grades of Ligament injuries (Sprains) and the treatment.

Answer 36

1) Grade 1: Local tenderness, normal joint movement
- Support, NSAIDS, encourage gentle use
2) Grade 2: slightly abnormal joint movement
- More support/joint protection, NSAIDS, elevate, encourage middle range of use
3) Grade 3: abnormal joint movement
- Requires orthopaedic consultation

Question 37

what are Strains and overuse injuries and how are they treated?

Answer 37

1) Strains can lead to Haematoma . Bleeding within and between muscles can result in extensive bruising and stiffness
- RICE regime and encourage pain-free movement
- sometimes Physiotherapy
2) Overuse injuries: e.g. Stress fractures, joint tenderness, ligament or tendon sprains, muscle stiffness
- Rest, NSAIDS, physiotherapy, improved training regime
- Severe stress fractures of foot might require cast