muscoskeletal intro Flashcards
what does the musculoskeletal system consist of?
Bones
Joints (point where two or more bones meet)
Muscles
Tendons (attach muscle to bone)
Ligaments (attach bone to bone, and help stabilise joints)
Cartilage and other connective tissues
Pharmacological Treatment OF Back pain
Drug treatment varies for acute back pain compared to sciatica or chronic back pain
NICE guidelines (NG59) recommends
Oral NSAIDs (lowest dose for shortest time)
Only offer weak opioids (with or without paracetamol) for acute lower back pain.
Consider an epidural of local anaesthetic for acute sciatica
Do not offer opioids for chronic back pain or sciatica
No longer recommend gabapentinoids or other anti-epileptics, oral corticosteroids, benzodiazepines or anti-depressants etc
Musculoskeletal Systemand physiological Ageing
of
bones
joints
muscles
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.
Musculoskeletal conditions: symptoms
PAIN is the main symptom of most musculoskeletal conditions:
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.
Where pain is felt might be misleading:
Pain that appears musculoskeletal may be cause by other disorders, e.g. back pain could be the result from a kidney infection/stone(s).
Musculoskeletal conditions: diagnosis
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, etc.
functions of bones
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).
different 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).
different 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).
what is the structure of spongey bone?
Less organized than compact bone.
Trabeculae align along positions of stress and exhibit extensive cross-bracing (important for providing bone reinforcement/strength).
what is bone remodelling and who does it effect the most?
Bone remodelling: refers to the formation of new bone to replace old bone.
Occurs constantly in growing children to allow for lengthening and/or thickening of bones (through the concerted actions of bone cells).
Occurs in adults in response to:
Trauma (fractures).
Stress (i.e. weight bearing exercise).
Metabolic changes (use or replenishment of e.g. calcium stores).
Bone: cell types
Osteoblasts: bone formation.
Osteocytes: maintain and repair bone tissue: “act as mechanosensors and orchestrators of the bone remodelling process”.
Osteoclasts: bone resorption (breakdown).
what can cause bone disease?
An imbalance between bone resorption and formation can result in bone diseases, such as osteoporosis (lecture 5).
what is osteoblast
Form new bone (“Blasts Build Bone”).
Are cuboidal cells located along the bone surface comprising 4–6% of the total resident bone cells.
Role in 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).
what is ostecytes
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, a of 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 is osteoclast
Bone resorption: remove deteriorating bone or unnecessary new bone (“Clasts Chew Bone”).
Large multi-nucleated cells (originate from bone marrow).
Secrete hydrogen ions to dissolve mineral matrix (i.e. hydroxyapatite crystals) and hydrolytic enzymes (e.g. collagenase) to degrade other components of bone.
