(PM3B) Musculoskeletal Therapeutics Flashcards
What comprises the musculoskeletal system?
(1) Bones
(2) Joints
(3) Muscles
(4) Tendons
(5) Ligaments
(6) Cartilage
What are tendons?
Attaches muscle to bone
What are ligaments?
Attach bone to bone
What is the most common musculoskeletal condition?
Osteoarthritis
What is the first line management of lower back pain?
(1) stretching/ strengthening/ aerobics/ yoga
then 2nd line
(2) NSAIDs
then 3rd line
(3) Weak opioids, e.g. codeine
When may surgery be required for lower back pain?
Prolapsed discs
What happens to bones with ageing?
Loss of bone mass in those >30yrs old
Bone loss accelerates post-menopause in women (due to drop in oestrogen levels)
What happens to joints with ageing?
Stiffen with age
Ligaments + tendons become more rigid
Cartilage thins, leading to increased friction
- arthritis
What happens to muscle with ageing?
Progressively lost from ~30yrs old
- sarcopenia
Reduced mass + strength leads to an increase in risk of injury
What is the main symptom of most musculoskeletal conditions?
Pain
What is bone pain?
Deep/ penetrating pain
What is muscle pain?
Often less intense than bone pain
What is joint, ligament, or tendon pain?
Stiff
Dull ache
Less intense than bone pain
Worse when moved/ stretched
When can back pain be misleading?
Kidney infection/ stone
How are musculoskeletal conditions diagnosed?
Observation of gait/ movement of the patient
Questions
Physical examination
Blood tests
- biomarkers
- inflammatory markers
- CT scan
- X-ray
What are some of the functions of bone?
(1) Support
- framework for attachment of muscles
(2) Protection
- of internal organs
(3) Movement
- levers + points of attachment for muscles
(4) Mineral storage
- reservoir for calcium
(5) Haematopoiesis
- housing of bone marrow
- production of blood cells + platelets
(6) Energy storage
- contain fats/ lipids
- yellow bone marrow
What is compact or cortical bone?
Hard + dense outer layer of bone
~80% of human skeleton
Comprised of proteins (1/3 bone mass) + hydroxyapatite (2/3 bone mass)
What is spongy bone?
Porous + highly vascularised
Storage of bone marrow
Low density + strength
Honeycomb-like structure
What is cancellous bone?
Porous + highly vascularised
Storage of bone marrow
Low density + strength
Honeycomb-like structure
What is trabeculae bone?
Porous + highly vascularised
Storage of bone marrow
Low density + strength
Honeycomb-like structure
What are the openings on the surface of spongy bone called?
Canaliculi
Describe the structure of trabeculae.
Align along positions of stress
Exhibit extensive cross-linking
- for reinforcement + strength
What is bone remodelling?
Formation of new bone to replace old bone
Occurs constantly in growing children
Allows for lengthening/ thickening of bones
When can bone remodelling occur in adults?
(1) Trauma
- fractures
(2) Stress
- weight-bearing exercise
(3) Metabolic changes
- replenishment of calcium stores
What are osteoblasts?
Bone cell type
Essential for bone formation
Cuboidal cells located along the bone surface
Secrete collagen proteins + proteoglycan
- mainly type 1 collagen
Initiate calcification
What are osteocytes?
Bone cell type
Maintain + repair bone
Comprise 90-95% of total resident bone cells
Located within lacunae
Surrounded by mineralised bone matrix
Connected to other osteocytes via canaliculi
When osteocyte dies, surrounding bone dies
What are osteoclasts?
Bone cell type
Breakdown bone
- removal of deteriorating bone
- removal of unnecessary new bone
Large multinucleated cells
- originate from bone marrow
Secrete hydrogen ions
- to dissolve mineral matrix
Secrete hydrolytic enzymes
- to degrade other components of bone
- e.g. collagenase
How can a condition such as osteoporosis be caused?
Imbalance between bone resorption and formation
What happens when an osteocyte dies?
Surrounding bone dies
What is the purpose of mechanosensors in bone tissue?
To sense bone health
What happens at the end of a bone formation cycle?
Osteoblast subpopulation become osteocytes in the matrix
How do osteocytes maintain bone?
Regulation of mineral ion exchange
How is an osteoclast formed?
(1) Haemopoietic prescursor
(2) Preosteoclast
(3) Osteoclast
can also be formed from:
(1) Mesenchymal stem cell
(2) Preosteoblast
(3) Osteoclast
What happens if the number of osteoclasts outweighs number of osteoblasts?
Osteoporosis
Weakens bone strength
What is the most common cause of fractures?
Trauma
What are some common symptoms of fractures?
(1) Pain
(2) Loss of function
(3) Deformity
(4) Crepitus
- grating/ popping/ cracking sound
(5) Bleeding can occur from bone/ surrounding tissues
What is the treatment for fractures?
(1) Immobilise + support limb
(2) Pain relief
- not NSAIDs as reports of delayed healing
(3) Immobilisation with casts/ surgical fixation of fracture
What should be advised to a patient with a fracture cast?
(1) Keep it dry
(2) Do not itch with sharp/ pointed objects
(3) Check visible skin for redness/ smell/ sores
(4) Rest with care
(5) Elevate regularly to reduce risk of swelling
(6) Contact doctor if tight or causing pain
What is compartment syndrome?
Serious limb-threatening condition
Caused by excessive swelling of injured muscles
Fibrous membrane surrounding muscle prevents expansion of swollen muscle
- Pressure builds within the muscle
Pressure in muscle restricts blood flow
- leads to hypoxia
- leads to death of muscle fibres
What are the symptoms of compartment syndrome?
Increasing pain in immobilised limb following fracture
What is the treatment of compartment syndrome?
Surgery to relieve pressure in constricted tissue
Amputation may be necessary if muscles/ nerves have died
What are some potential complications of fractures?
(1) Compartment syndrome
(2) Pulmonary embolism
What is a pulmonary embolism?
Sudden blockage of artery in lung by a blood clot
- usually from leg vein
Common + fatal
- following serious hip/ pelvic fractures
- less common in lower leg fractures
- very rare in upper body fractures
Why does a fracture increase risk of pulmonary embolism?
(1) Trauma to leg
(2) Forced immobility
(3) Reduced blood flow to veins
What are some symptoms of pulmonary embolism?
(1) Chest pain
(2) Cough
(3) Shortness of breath
Describe the prophylaxis of pulmonary embolism following fractures.
(1) Anticoagulants
- e.g. heparin
- often given with warfarin
- reduces occurrence of blood clots
What is a joint?
A junction between 2 or more bones
What types of joint are there?
(1) Ball + socket
(2) Hinge
What components of a joint reduce risk of damage?
(1) Articular cartilage
(2) Synovial membrane + fluid
(3) Stabilising ligaments
What components are present in the knee joint?
(1) Meniscus
(2) Bursa
(3) Patella
(4) Ligaments
What is the meniscus in the knee?
Lateral/ medial
Cushion of fibrous cartilage
Ensures even distribution of weight on the joint
What is the bursa in the knee?
Fluid-filled sac
Lined by synovial membrane
Provides a cushion between bone + tendons
What is the patella in the knee?
Knee cap
Protects knee joint
What are ligaments comprised of?
Collagen + elastin fibres
Provide stability bone-bone
Allow a range of movement
Describe the structure of tendons.
Tough bands of connective tissue
- mostly comprised of collagen
Contained within a sheath
Lubricated to allow movement without friction
What types of muscle are there?
(1) Skeletal
- striated
(2) Smooth
(3) Cardiac
What is striated muscle?
Skeletal muscle
Bundles of contractile fibres
Responsible for movement + posture
Arranged in opposing groups
What are satellite cells?
Myogenic stem cells
Responsible for post-natal growth/ repair/ maintenance of skeletal muscle
How do satellite cells cause muscle growth?
(1) Activates by injury/ trauma
(2) Differentiate asymmetrically into another satellite cell + a myoblast
(3) Myoblast matures
(4) Mature myoblast fuses
How do satellite cells cause muscle repair?
(1) Activates by injury/ trauma
(2) Differentiate asymmetrically into another satellite cell + a myoblast
(3) Myoblast matures
(4) Mature myoblast fuses
How do satellite cells cause maintenance of skeletal muscle?
(1) Activates by injury/ trauma
(2) Differentiate asymmetrically into another satellite cell + a myoblast
(3) Myoblast matures
(4) Mature myoblast fuses
What is a strain?
Damaged/ torn muscle
e.g. hamstring injury
What is a sprain?
Damaged ligaments
e.g. ACL
What is tendinitis?
Inflammation of tendon
What are shin splints?
Fractures of shin bone
What is the primary treatment of sporting injuries?
RICE
R = Rest
- minimises internal bleeding + prevents further injury
I = Ice
- Reduces pain + swelling
C = Compress
- Reduces swelling + further risk of injury
E = Elevate
- reduces swelling
- area should be above the level of your heart
(1) What is the purpose of icing a sporting injury?
(2) How should it be done?
(1) Cold reduces pain + inflammation
(2)
- Wrap ice in towel and apply for 10 minutes
- Remove for 10 minutes
- Repeat for 60-90 minutes to prevent a cold injury
Why is ice applied and removed cyclically in treatment of a sporting injury?
To prevent a cold injury
