Muscoskeletal system

Question 1

What does the Musculoskeletal system consist of? (6)

Answer 1

1. Bones
2. Joints
3. Muscles
4. Tendons
5. Ligaments
6. Cartilage + other connective tissue

Question 2

What is the highest incidence group for back pain?

What % of people will be affected?

Answer 2

16-44 year age group

80%

Question 3

What is the ratio of working days lost due to back pain?
How many days would a person take off in a year?
What is the estimated cost for the NHS?

Answer 3

1 in 6 working days lost

average 17.4 days off work

~420 million

Question 4

Describe the condition of bones with ageing?

Answer 4

Loss of bone mass occurs >30 years in both men and women

Loss accelerates post-menopause in women

Question 5

Describe the condition of joints with ageing?

Answer 5

Joints stiffen with age as ligaments and tendons become more rigid.
Cartilage thins leading to increased friction/wear and tear

Question 6

Describe the condition of muscle with ageing?

Answer 6

Progressively lost from approx. 30yrs (sarcopenia), reduced mass and strength increases risk of injury

Question 7

Define sarcopenia

Answer 7

the loss of skeletal muscle mass and strength as a result of ageing.

Question 8

Symptoms of musculoskeletal conditions? Describe each

Answer 8

1. Pain.
   Bone (deep penetrating or dull pain), e.g. trauma, infection and cancer
   Muscle (less intense that bone pain) e.g. trauma, inflammation and cramp/spasm
   Other joint pain (stiff, dull ache, worse when moved) e.g. trauma, sprains, arthritis
2. Swelling
3. Inflammation
4. Bruising
5. Loss of movement

Question 9

Diagnosis of musculoskeletal conditions

Answer 9

1. observation of movement
2. Questions? Pain with movement, rest?
3. Physical examination
4. Blood tests e.g. Biomarkers, Inflammatory markers
5. X-rays, Computed tomography (CT) scans

Question 10

What are the (6) functions of the bone?

Answer 10

1. Support - Framework for attachment of muscles etc
2. Protection - Protects internal organs from injury (i.e. rib cage, vertebrae and skull)
3. Movement - Enable body movement by acting as levers and points of attachment for muscles
4. Mineral storage - Reservoir for calcium (99% of body’s calcium) and phosphorus (95% of body’s 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 11

What are the two types of bone

Answer 11

1. Compact/Cortical bone

2. Spongy/Cancellous/Trabeculae Bone

Question 12

Describe the structure of Compact/cortical bone

Answer 12

Hard, dense outer layer of bone consisting of:

• Proteins (collagen (95%), proteoglycans etc) make up 1/3 of bone mass
• Hydroxyapatite (mostly calcium phosphate) makes up 2/3 of bone mass

Question 13

Describe the structure of spongy/cancellous/Trabeculae bone

Answer 13

Low density and strength (honeycomb structure)

High surface area

Question 14

Describe bone remodelling.

Answer 14

is the formation of new bone to replace old bone.

Occurs constantly in growing children to allow for lengthening and/or thickening of bones

Occurs in adults in response to:
trauma (fractures)
stress (i.e. weight bearing exercise)
Metabolic changes (use or replenishment of calcium stores)

Question 15

What are the three cell types involved in bone remodelling ?

Answer 15

1. Osteoblasts*
2. Osteocytes
3. Osteoclasts*

Question 16

What is the function of Osteoblasts?

Answer 16

Form new bone. (Blasts Build Bone)

Synthesise and secrete collagen and other organic components of bone matrix

Initiate calcification – laydown of calcium

Located in bone membranes (i.e.periosteum and endosteum)

Question 17

What is the function of Osteocytes?

Answer 17

Osteoblasts that have become surrounded by bone matrix

Connected to other osteocytes and the bone surface via canaliculi

Role to maintain bone, not by synthesising new bone, but by regulating mineral ion exchange

Osteocyte dies, surrounding bone dies

Question 18

What is the function of Osteoclasts?

Answer 18

Remove deteriorating bone or unnecessary new bone. Clasts Chew Bone

Large multi-nucleated cells

Secrete hydrogen ions to dissolve mineral matrix and hydrolytic enzymes (i.e. collagenase) to degrade other components of bone.

Question 19

Important note about origins of Osteoblasts and Osteoclasts

Answer 19

They do NOT originate from the same stem cells.

Question 20

What happens if there is an inbalance of Osteoblasts and Osteoclasts?

Answer 20

Too much Osteoblasts compared to OsteoClasts leads to Osteoporosis and Paget’s disease which is the lay down of too much unorganised bone

Question 21

Define Fracture, and what can cause it to occur and the presenting symptoms.

Answer 21

Fracture: a break in the bone, commonly associated with injury surrounding tissues.

Trauma is the most common cause, excessive use of steroids and other conditions such as osteoporosis can weaken bones.

Common symptoms:
Pain
Loss of function
Deformity
Crepitus (grating, popping, cracking)
Bleeding can occur from bone or surrounding tissues

Question 22

What are the phases of fracture repair?

Answer 22

1. Inflammatory phase
2. Inflam/Repair phase
3. Repair phase
4. Remodelling

Question 23

Describe the 1. Inflammatory phase of fracture repair

Answer 23

Haematoma (clot) formation. Lack of blood supply may lead to bone death. Area is painful, swollen, inflamed and bruised.

Question 24

Describe the Inflam/Repair phase of fracture repair

Answer 24

Callus (fibrous tissue + cartilage) formation

• Debris cleared by macrophages.
• Revascularisation occurs.
• Fibroblasts produce collagen that spans break
• Chrondroblasts begin to secrete cartilage matrix
• Osteoblasts begin to form spongy bone

Question 25

Describe the Repair phase of fracture repair

Answer 25

Bony Callus Formation - Bone trabeculae increase in number - Fibrocartaginous callus is converted into bony callus of spongey bone - Typically takes 6-8 weeks

Question 26

Describe the Remodelling phase of fracture repair

Answer 26

``` Bone remodeling (months) - Bony callus is continually remodelled - Bone structure is restored: Osteoclasts remove temporary supportive structures Osteoblasts rebuild compact bone ```

Question 27

Describe the treatment for fractures

Answer 27

Immediate emergency treatment: - immobilise + support limb, elevate, ice - pain relief - NOT NSAIDs ( reports of delayed healing) - Open fractures need immediate treatment/surgery to clean and close wound - Closed fractures less urgent Further treatment required - Immobilisation with casts or traction - Surgical fixation of fracture (rods, plates, hip replacement

Question 28

What complications of fractures can occur?

Answer 28

1. Compartment syndrome: serious, caused by excessive swelling of injured muscle. Fibrous membrane surrounding muscle prevents expansion of swollen muscle and pressure builds within muscle Pressure in muscle restricts blood flow and this leads to hypoxia, further injury of muscle and even muscle death Symptoms: increasing pain in immobilised limb after fracture Emergency medical treatment required! Surgery to relieve pressure in constricted tissue. If muscle/nerves have died, amputation might be necessary. 2. Pulmonary embolism Sudden blockage of artery in lung by blood clot (usually travels from leg vein) Common fatal complication after serious hip and pelvic fractures, less commonly in lower leg fractures and v. rarely in fractures of upper body Risk increased due to combination of trauma to leg, forced immobility and reduced blood flow in veins due to swelling Symptoms: chest pain, cough, shortness of breath Emergency medical treatment required! In those at risk of pulmonary embolism, heparin, warfarin etc can be given to reduce the occurrence of blood clots

Question 29

Define "joint" and describe features

Answer 29

Joint - junction between 2 or more bones Range of movement vary: Joints in skull, Shoulder ( ball and socket), Finger (hinge) Consists of components that ensure stability and reduce the risk of damage: - Articular cartilage - Synovial fluid and membrane - Stabilising ligaments

Question 30

What additional features do knee joints exhibit?

Answer 30

- Meniscus, a cushion of cartilage that ensures even distribute the body weight in joint - Bursa, a fluid filled sac that cushions bone and tendon - Patella, protection of joint - Ligaments (5) provide stability while allowing range of movement

Question 31

Define Ligament

Answer 31

Tough fibrous cords of connective tissue that stabilise and strengthen joints

Question 32

Define Tendons

Answer 32

Tough bands of connective tissue (made up mostly of collagen) Attach muscle to bone Contained within a sheath and lubricated to allow movement without friction

Question 33

Define Bursa

Answer 33

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 34

Describe Skeletal muscle

Answer 34

Skeletal (Striated) Muscle Bundles of contractile fibres that are responsible for our movement and posture Attached to bones and arranged in opposing groups Biceps bend elbow, triceps straighten it Opposing arrangement ensures smoothness of movement and limits risk of damage Size and strength of muscle increase and decrease with workload

Question 35

Which cells are responsible for the growth and repair of skeletal muscle?

Answer 35

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

Question 36

What types of sporting injuries can occur?

Answer 36

Strains Damaged/torn muscle i.e. Hamstring Sprains Damaged/torn ligaments i.e. ACL injury Tendinitis Inflammation of tendon Stress fractures of foot Shin splints Fractures of shin bone

Question 37

What is the Treatment of sporting injuries

Answer 37

RICE Rest Minimises internal bleeding and swelling, prevents further injury Ice Reduces pain and inflammation Ice 10 minutes, remove 10 minutes, ice 10 minutes etc for 60-90 minutes to prevent cold injury Compression reduced swelling, risk of further injury Elevation Reduce swelling

Question 38

Describe the grading system for Ligament injuries (sprains)

Answer 38

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

Question 39

Treatment options for Strains

Answer 39

Haematoma Bleeding within and between muscles can result in extensive bruising and stiffness RICE regime and encourage pain-free movement Physiotherapy

Question 40

Treatment options for overuse injuries

Answer 40

Stress fractures, joint tenderness, ligament or tendon sprains, muscle stiffness Rest, NSAIDS, physiotherapy, improved training regime Severe stress fractures of foot might require cast