Musculoskeletal conditions Flashcards
what does the Musculoskeletal system consists of?
- Bones
- Joints (Junction between 2 or more bones).
- Muscles
- Tendons (attach muscle to bone)
- Ligaments (attach bone to bone, and help stabilise joints)
- Cartilage and other connective tissues
what do NICE guidelines on low back pain and sciatica recommend?
1st line: exercise, e.g. stretching, strengthening, aerobics or yoga
then: NSAIDs: ibuprofen, aspirin (lowest dose).
Move on to weak opioids e.g. codeine.
surgery (prolapsed disks)
how does physiological Ageing affect the Musculoskeletal System in terms of bones, joints and muscle?
Bones: Loss of bone mass occurs >30 years in both men and women.
Loss accelerates post-menopause in women (oestrogen levels drop).
Joints: Joints stiffen with age as ligaments and tendons become more rigid.
Cartilage thins leading to increased friction/wear and tear (–> arthritis).
Muscle: Progressively lost from ~30yrs (sarcopenia), reduced mass and strength increases risk of injury.
what is the main symptom of most musculoskeletal conditions?
other symptoms?
Bone pain (trauma, infection, cancer): deep, penetrating or dull pain.
Muscle pain (trauma, inflammation, cramp/spasm etc): often less intense than bone pain but unpleasant.
Other joint and tendon/ligament pain (trauma, sprains, arthritis and so on): stiff, dull ache, less intense than bone pain; worse when moved and/or stretched.
swelling, bruising, inflammation, loss of movement
Musculoskeletal conditions- how is a patient diagnosed?
Observation of gait/movement of the patient.
Questions: pain with movement, at rest, at night, any trauma?
Physical examination (swelling, bruising, tenderness, heat).
Blood tests (biomarkers, inflammatory markers), computed tomography (CT) scans, X-ray
what are the functions of bone?
Support: provides a framework for attachment of muscles; gives us our ‘human shape’
Protection: protects internal organs from injury (i.e. rib cage, vertebrae and skull).
Movement: enables body movement by acting as levers and points of attachment for muscles.
Mineral storage: reservoir for calcium (99% of body’s calcium) and phosphorus (85% of body’s phosphorus).
Haematopoiesis: certain bones house bone marrow which is essential for production of blood cells (red and white, also platelets).
Energy storage: certain bones contain fats/lipids (yellow bone marrow).
what are the two types of bones?
Compact/Cortical bone: Hard, dense outer layer of bone (~80% of human skeleton) consisting of:
- Proteins (primarily type I collagen (95%) make up ~1/3 of bone mass.
- Hydroxyapatite (mostly calcium phosphate) makes up ~2/3 of bone mass.
Spongy/Cancellous/Trabeculae Bone:
- Porous and highly vascularised.
- Storage of bone marrow.
- Low density and strength (lattice-like, ‘honeycomb’ structure: i.e. trabeculae).
spongy bone structure
Less organized than compact bone.
Trabeculae align along positions of stress and exhibit extensive cross-bracing (important for providing bone reinforcement/strength).
(forms a lattice like structure within the layer of compact bone. The trabeculae align in a pattern that provides cross-bracing against the stresses that are placed on the bone. This cross-bracing structure is vital to provide bone strength. A loss of bone density is observed as we age and it is the loss of spongy bone in osteoporosis that leads to increased risk of fragility fractures. Someone with osteoporosis may break a bone doing something normal, like falling from a seated position in a chair onto the floor.)
define Bone remodelling
when does it occur?
the formation of new bone to replace old bone.
Occurs constantly in growing children to allow lengthening and thickening of bones.
Occurs in adults in response to: Trauma (fractures), Stress (i.e. weight bearing exercise), Metabolic changes (use or replenishment of e.g. calcium stores).
name 3 types of bone cells and their roles
Osteoblasts: bone formation.
Osteocytes: maintain and repair bone tissue: act as mechanosensors and orchestrators of the bone remodelling process.
Osteoclasts: bone resorption (breakdown).
what happens if there is an imbalance between bone resorption and formation?
can result in bone diseases
When osteoclast activity leads to greater breakdown of bone than new bone formation, you get conditions such as osteoporosis.
when osteoblasts lay down too much bone, you get conditions such as pagets disease/ osteomalacia
what are osteoblasts and how do they form new bones?
cuboidal cells located along the bone surface comprising 4–6% of the total resident bone cells
synthesis of bone matrix: osteoblasts secrete collagen proteins (mainly type I collagen) and proteoglycan.
Initiate calcification (sulphated proteoglycans immobilise calcium ions stored within matrix vesicles).
role of osteocytes?
location?
what happens if Osteocyte dies?
Comprise 90–95% of the total resident bone cells (derived from mesenchymal stem cell lineage through osteoblast differentiation).
Located within lacunae surrounded by mineralized bone matrix:
At end of a bone formation cycle, osteoblast subpopulation become osteocytes in the matrix.
Connected to other osteocytes (via their cytoplasmic processes) and bone surface via canaliculi.
Role to maintain bone by regulating mineral ion exchange.
Osteocyte dies, surrounding bone dies.
what are osteoclasts?
role?
how do they work?
Large multi-nucleated cells (originate from bone marrow).
Bone resorption: remove deteriorating bone or unnecessary new bone.
Secrete hydrogen ions to dissolve mineral matrix (i.e. hydroxyapatite crystals) and hydrolytic enzymes (e.g. collagenase) to degrade other components of bone
origins of bone cells?
Osteoblasts and osteocytes are differentiated from mescenchymal stem cells in the bone marrow
osteoclasts are differentiated from haematopoietic stem cells in the bone marrow.
define fracture
A break in a bone, commonly associated with injury surrounding tissues
what is the most common cause of fractures?
other causes?
trauma
underlying conditions such as osteoporosis, infections or bone tumours can weaken bones and make fractures more likely to occur.
symptoms of fractures
Pain.
Loss of function.
Deformity.
Crepitus (grating, popping, cracking sound and/or sensation).
Bleeding can occur from bone or surrounding tissues.
treatment of fractures
Immediate emergency treatment required:
- Immobilise and support limb, elevate, ice.
- Pain relief: not NSAIDs for frail or older adults (reports of delayed healing). Pain management in adults (16 years+): paracetamol, then move on to codeine.
- Open fractures need immediate treatment or surgery to clean and close wound. (a fracture when the bone has broken through the skin)
- Closed fractures less urgent but, until treated, patient experiences pain and loss of function. (Sometimes, swelling can make it difficult to see hairline or greenstick fractures so the limb might be supported and treatment delayed until swelling has subsided and a clear x-ray of the fracture can be taken)
Further treatment required:
- Immobilisation with casts or being placed in traction.
- Surgical fixation of fracture (using rods, plates, hip replacement).
tips for Living with a cast
Keep it dry. You can now get fiberglass casts with waterproof liners.
Never relieve itch with sharp or pointed objects. (could injure themselves and get an infection)
Check skin visible edge of cast for smell, redness or sores.
Rest with care to prevent cast chaffing or digging into skin; pad rough edges.
Elevate cast regularly to reduce risk of swelling.
Contact doctor if cast feels excessively tight or causes persistent pain.
name two complications that can arise with fractures
explain what they are, how they occur, symptoms and treatments.
Compartment Syndrome: serious limb-threatening condition caused by excessive swelling of injured muscles:
- 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 potentially death of muscle fibres.
- 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.
Pulmonary embolism: sudden blockage of an artery in the lung by a blood clot (usually travels from leg vein):
- Common fatal complication after serious hip and pelvic fractures, less common in lower leg fractures; very rare 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, anticoagulants, i.e. heparin (often given together with warfarin), can be given to reduce the occurrence of blood clots.
what do joints consist of?
Consist of components that ensure stability and reduce risk of damage:
- Articular cartilage.
- Synovial membrane and fluid.
- Stabilising ligaments.
what additional features does a knee joint have?
Meniscus: a cushion of fibrous cartilage which ensures an even distribution of body weight on the joint.
Bursa(e): a fluid-filled sac (lined by synovial membrane) that provides a cushion between bone and tendons, or muscles around a joint.
Patella (knee cap): protects the knee joint.
Ligaments: connective tissue (collagen and elastin fibres) which provide stability (bone to bone), while allowing a range of movement.
what are tendons and what is their function?
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.







