Bones Flashcards
What are the functions of a bone:
Must be good at regulating themselves in order to:
Provide structure
Mobility
Support
Protection for the body
Storehouse for essential minerals
Typical long bone
What is found at either end?
Distal epiphysis and proximal epiphysis
Both contain articular cartilage
Typical long bone
Shaft of bone is-
What is found in the bone?
Shaft of bone is the diaphysis. Outer part is covered in compact bone which makes the bone strong
In the Bone is the medullary cavity. Endosteum (sheath) contains lots of cells and a bit of connective tissue, bone marrow and blood vessels
Typical long bone
What is the metaphysis?
A widened area connecting both proximal and distal epiphysis to the diaphysis
This separates the epiphyseal plate. This is where bone growth occurs
Typical long bone
What is the periosteum?
Periosteum surrounds the entire bone and has both an outer and inner layer
Outer - tendons and ligaments will attach
Inner - has cells
Bone as a connective tissue (CT)
What makes up the matrix?
Collagen fibres for flexibility and ground substance which gives firmness
25% water, 25% collagen 50% crystallised mineral salts - calcium hydroxyapatite.
Bone as a CT
Organisation of osseous tissue:
1) compact (cortical)
2) spongy (trabecular/canellous)
Types of osseous tissue
1) compact -
80% of total mass - denser than spongy but less flexible
Gives bone strength
Solid hard layer external layer of ALL bones
Osteon - concentric rings (lamellae) of calcified matrix surrounding vertically orientated blood vessels - lay next to each other along a vertical axis
More lamellae found between each osteon
Extra cellular fluid and bone cells found between lamellae
Canaicular projects at bone cells and have a role in nutrient regulation.
Takes vertical impact better than lateral and transverse impact
Types of osseous tissue:
2) spongy
20% of total mass - gives bone lightness and is a good shock absorber
Found in inner parts of axial skeleton and epiphyses of long bones
Lattice like structure
Well organised along lines of stress - giving strength and resisting stress and forces without breaking
Osteocyctes (bone cells) in lacunae (pit/lake) on the surface of the trabeculae
Nutrients directly from the blood in the medullary cavities
Helps withstand stresses from multiple directions
Blood vessels aren’t in the matrix
Cell types of bone
1) osteogenic/osteoprogenitor -
Undifferentiated cells
They wait to receive information about making a new bone
These cells can divide when stimulated - the daughter cells produced are osteoblasts
These are the ONLY bone cell that can divide
Cell types of Bone
2)osteoblasts -
These are affected by age
Build matrix and collagen fibres. Come from osteogenic cells and form bone tissue
Cells become trapped in own system of bone, they are then referred to as osteocytes
Osteoblasts sit on outside of bone whereas osteocytes sit inside
Cell types of bones:
3) osteocytes -
Mature bone cells
Have to maintain the bone and monitor nutrients. Sit inside bone
Cell types of bone:
4) osteoclasts -
Clear bone cells. Largest bone cell
Functions in reabsorption - the destruction of the bone matrix
Have a ruffed border - stick themselves to bone and release enzymes to destroy it
Minerals like calcium will be given to the rest of the body.
Where are the different types of bone cells located?
Osteogenic - endostium in inner layers of periostium
Osteoblasts - surface of bone
Osteocytes - lacunae of compact and spongy bone
Osteoblasts - surface of bone
How does bone grow?
Grows in length as cartilage grows on epiphyseal side of plate
And old cartilage underneath is replaced by bone (it calcifies)
18-25 this will stop
Growing shaft is remodelled width ways by blood vessels in bone stimulating osteoblasts to make more bone to increase width
This is called appositional growth
Length and width MUST grow at same time
What can go wrong and affect bone growth?
Osteoporosis (low bone density)
Osteogenesis imperfecta - genetic disorder whereby you don’t produce enough collagen therefore bones become brittle
Paget’s disease of bone whereby bone is replaced faster than usual and not made properly so is weak
Bone cancer
Bone infections
Where do different vessels supply in bones
Periosteal arteries -
Nutrient arteries -
Periosteal - periosteum and outer osteons of compact bones
Nutrient - medullary cavity and osteons of inner compact bone
Where do different vessels supply in bones
Metaphyseal arteries -
Epiphyseal arteries -
Metaphyseal - spongy bone and marrow in this area
Epiphyseal - spongy bone and marrow in this area
Dynamic skeleton
Bone remodelling affected by:
Age
Mechanical stress
Genetics and environment - black people have increased bone density whereas Asian most have decreased density
Calcium and phosphate levels - calcium deficiency results in bones being broken in order to obtain calcium
Hormones
Why does age has a big impact on bone remodelling ?
Demineralisation from the age of 40 - osteopenia
Reduces by 1% each year
Worse in woman
HRT can be given to keep oestrogen levels up to help prevent osteoporosis
Mechanical stress and impact on bone remodelling:
Weight bearing - so important for bone development and healing
Lack of activity results in loss of bone
Weight bearing activities build bone
Lack of mechanical stress reduces bone density
Bone disorders of development:
Agenesis - limb doesn’t/only partially forms
Osteogenesis imperfecta - genetic disorder - brittle
Spina bifida - spinal processes don’t form
Achondroplasia - long bones don’t form properly - dwarfism
Bone disorders of remodelling:
Age
Hormone levels
Calcium and phosphate level
Mechanical stress
Bone endocrine disorders:
Gigantism - produce too much growth hormones (childhood)
Acromegaly - bones increase in density and not length (adulthood)
Pituitary dwarfism
Hyper/hypoparthyroidism
Post menopausal osteoporosis
Bone disorders nutritional problems:
Rickets (Vit D)
Osteomalacia
Scurvy (Vit C)
Disorders linked to aging:
Osteopenia -
Osteoporosis -
Osteopenia - inadequate ossification. Osteoblasts activity decreases from 30-40 years
Jaw, vertebrae and epiphyseal areas are most commonly affected
Osteoporosis - decrease in bone mass greater for age/gender than expected
Mainly females and over 70
Low activity therefore not weight bearing puts you at really high risk
Osteoporosis
Primary -
Secondary -
Primary - simple form in elderly. Accelerated bone loss but within normal range for patients age/gender
Secondary - has a different cause rather than age or post menopause eg metabolic bone disease or serve malnutrition or some steroids
Fractures - named according to
1) severity (6 types) -
Open/compound - bone breaks skin
Impacted - one fragment driven into another
Comminuted - breaks into loads of pieces
Closed/simple - less soft tissue involvement
Displaced - fragments moved from original position
Compressed
Fractures - named according to:
2) shape (5 types) -
Spiral - twisting forces cause this
Oblique - twisting and direct force, common in ankles
Greenstick - only in children. Increased collagen and bones more bendy
Depressed - skull fractures
Transverse - straight across horizontal axis
Fractures - named according to
3) position (4 types) -
Distal/proximal 1/3
Neck
Shaft
Epiphyseal
Stages of fracture healing
1) haematoma formation
Bleeding
Clot produced in 6-8 hours, bone cells die
Inflammation brings in phagocytic cells. Clear up debris - can take up to 3-4 weeks
New capillaries grow into damaged area
Stages of fracture healing
2) fibrocartilagenous callus formation -
Fibroblasts invade the procallus and lay down collagen - this unites ends of bone, but is weak and only temporary
Chondroblasts produce fibrocartilage
Stages of fracture healing
3) formation of bony callus
Osteoblasts secrete spongy bone that joins the broken ends of bone
Lasts 3-4 months
Fracture site is firmly held - bone is ready to hold itself
Stages of fracture healing
4) bone remodelling
Compact bone replaces the spongy in the bony callus
Surface is remodelled back to normal shape therefore weight bearing is essential
Sometimes a palpable lump will remain
What factors affect fracture healing?
Fracture type
Site of fracture eg upper/lower
Vascular supply - lack of. Makes healing difficult
Age of patient
Movement at site
Separation of bone ends - big gap is more problematic
Infection
Bone pathology
clinical features of fractures:
Pain and tenderness
Swelling and bruising
Deformity and angulation
Impaired function
Shock
Treatment for a closed fracture -
Simple fracture with minimum soft tissue damage
Immobilisation - sling/cast/splint
Rehab not always required
Treatment for an open simple fracture -
Open and simple fractures need high level of immobilisation near the joint. Often comminuted fractures
Immobilisation - open reduction internal fixation (ORIF) - normally permanent eg metal rod inside
Rehab may commence immediately
Treatment for an open compound fracture -
Open/compound fractures
Including tissue damage and at risk of infection
Immobilisation - open reeducation external fixation (OREF) - screw and metal on outside of person and drilled in, but sit outside. Less invasive and can take it out when done.
Rehab may commence immediately
Complication of fracture healing:
Delayed mail/non-union - not healing
Avascular necrosis
Sudecks atrophy - 40-60yr females increased risk. Disturbance in sympathetic nervous system. Disproportionate chronic pain
Compartment syndrome - increased bleeding and swelling - compress themselves
Myositis ossificans - bone laid down in muscle by accident
Blood vessel/nerve damage
Tendon tears and injury
Fat embolus - long bones - yellow bone marrow leaks, can cause stroke/heart attack
Osteoarthritis
Growth impairment
Neck of femur fracture - aetiology:
Impact/tramua/fall
Osteoporosis
Age
RTA
Balance issues
Thyroid issues
Low BP and dizziness
Neck of femur fracture - signs and symptoms -
Pain in hip/upper leg
May have radiating pain to knee
Swelling and bruising around hip/upper leg
Unable to weight bear
Difficulty moving hip/leg
Neck of femur fracture healing- complications to healing -
Poor blood supply - cause delayed healing or tissue death (avascular necrosis)
Infection - higher risk after surgery
Delayed union or non union - insufficient blood flow therefore delayed healing which can cause more pain and weakness in the area
Misalignment and joint issues - impact to bones can affect the nearby nerves and blood vessels
Neck of femur fracture - interventions/management -
Combo of surgery, meds and rehab
Surgery options - total hip replacement, dynamic hip screw etc
Meds used to manage pain
Rehab will begin as early as possible - often on same day/the day following
Neck of femur fracture -prognosis -
Likely cause/outcome of a disease or medical condition
A serious injury
Post surgical complications eg infection
For fri/elderly, death within first month
1 in 10 die within first month
Will depend on health prior to injury
For young and healthy, 12-16 weeks
Old typically 3-6months
Potts fracture - mechanism of injury:
Where ankle joint is forced into extreme position beyond normal ROM
In sport, normally as a result of a forced plantar flexion/inversion movement
Common causes: traumatic injuries, sport related accidents, motor vehicle accidents
Potts fracture signs and symptoms
Pain
Tenderness
Swelling
Bruising
Inability to weight bear on injured ankle
Potts fracture - complications to healing or recovery
Chronic pain
Ankle joint instability
Insufficient rest therefore increasing pain
Excessive weight bearing exercises
Soft tissue flexibility and strength is lost with inactivity during recovery
Potts fracture - intervention and management
Focus on promoting healing and restoring function
Cast for closed fracture and internal/external fixation for open fracture
Immobilisation
Pain management
ROM exercises
Strengthening exercises eg ankle pumps or using a resistance band
Potts fracture - prognosis
Some cases, plaster casts from knee downwards for 6 weeks and crutches
If severe and bone displaced, may require realignment and then a protective boot or cast
Less severe, treated with ankle brace or walking foot
Once healed, fracture rehab program used for ankle. Wobble board and proprioceptive training
Pathological fractures - aetiology
Osteoporosis - weakens bones therefore more likely to break
Osteomalacia - softens bones due to lack of Vitamin D pagers disease - bones remodel more often than needed, therefore weaker and more brittle
Osteogenesis imperfects - genetic condition, insufficient collagen produced
Pathological fractures signs and symptoms -
Don’t always have symptoms as can occur during ‘normal activity’
If symptoms, can include mild-severe pain, bruising, tenderness, swelling, numbness/tingling
Pathological fractures complications to healing -
Depending on fracture location you may need a pin,plate or screw to hold bone in place
Surgery may be required
Infection is a risk for chronic and surgical wounds
Pathological fractures interventions/management
Main aim of treatment is pain relief
If underlying condition weakens bones but doesn’t impact healing ability, fracture will only require a cast or splint
If bones ability to heal has been lessened by the underlying condition and surgery is not an option, main focus of treatment should be on treating the condition, as well as the fracture
Pathological fractures - mechanism of injury
Tumours near a bone
Osteoporosis
Secondary to metastatic disease instead of primary bone tumours
Green stick fracture - aetiology
Falls (especially when trying to break a fall with outstretched hands)
Sport injuries, compact sport injuries
Car accidents
Green stick fracture - aetiology
Falls (especially when trying to break a fall with outstretched hands)
Sport injuries, compact sport injuries
Car accidents
Green stick fractures - signs and symptoms
Pain
Swelling and puffiness around area
Deformity
Bruising
Limited ROM
Tenderness
Green stick fractures - complications to healing/recovery
Malunion - following treatment when broken bone doesn’t line up properly
Non-union - durian recovery bone may not grow back together fully or at all
Acute compartment syndrome - excessive bleeding/swelling in area cut of nerve/blood supply and cause permanent damage
Others include; avascular necrosis, tendon injury, growth impairment
Green stick fractures - interventions/management
Typically area is immobilised by a cast/splint for 6 weeks
In severe cases - bone reduction is bone is too bent curved to straighten fracture
Internal/external fixation may be required
Follow up with x-rays
Green stick fractures prognosis:
Around 6 weeks to heal, can be affected by severity of fracture and high bone fracture occurs in
Children who experience this fracture in forearm may have increased risk f fracture in same bone in the future
Colles’ fracture - aetiology
Occur after forceful impact to wrist like falling on outstretched hand
Fall sends force through bones resulting in displacement of distal radius
More likely in the elderly bc of brittle bones, or children bc of softer bones
Severity of injury depends on the amount of fore and position of the wrist
Colles’ fracture signs and symptoms
Decreased ROM
Pain during fexion of wrist
Tenderness
Swelling
Bruising
Deformity
Colles’ fracture - complications to healing/recovery
3-4 months typical healing period
Realignment and immobilisation is essential
Wrist stiffness most common complication but normally improves
Carpal tunnel syndrome - nerves may be compressed causing pain and numbness
Osteoarthritis - can occur during recovery due to lower bone density putting you at higher risk
Colles’ fracture - interventions/management
External fixation
Internal fixation
Bone substitutes - synthetic material used to treat bone defects
Colles’ fracture. Prognosis
Patients frequently heal well with no complications after 6-12 weeks
Ca take up to a year to fully heal to before fracture state
Smoking, diabetes, medications can all sow down recovery rate
Boxers fracture aetiology -
A break in the neck of the fifth metacarpal bone, usually caused by punching a hard object with clenched fist
Interosseous muscle and flexor tendons pull on the bone which can cause bone to shorten or become angled
Most common in people age 10-40
Athletes who play physical sport
People who have osteoporosis
Boxers fracture signs and symptoms
Painful bruising and swelling in back and front of the hand
Pain in dorsal side of hand around 5th metacarpal bone
Bent claw like pinky finger - looks visibly out of line
Limited ROM around 4th and h
Boxers fracture. Complications to healing -
6 weeks after initial recovery
Malunion and non union
Joint stiffness
Grip weakness - reduced grip and pain when flexing hand
Chronic pain
Infection - increased risk if bone breaks through skin
Boxers fracture - interventions/ management
Splints used for immobilisation
Braces used for support
Often kept above heart to reduce blood flow and limit swelling and pain
Closed reduction may be necessary, 5th metacarpal will be pushed laterally to realign broken bones
Anaesthetics to numb pain
Boxers fracture - prognosis
Takes around 6 weeks for fracture to heal then further 6 weeks for bone to realign to full strength
How long depends on severity
Chronic pain, weakness and hand function limitations may result if condition isn’t properly assessed
