Musculoskeletal System Flashcards
What is a fracture?
Dissolution of bony continuity with/without displacement of fragments.
State 5 types of soft tissue damage which may accompany a fracture.
Torn vessels
Bruised muscles
Laceration of skin
Injured internal organs
Contused nerves.
State 4 forces which cause a fraction to occur.
Torsion
Bending
Compression
Shear
Why may a fraction occur?
Force is applied which exceeds the bone strength and elasticity
State the 3 causes of fracture
Indirect Trauma
Direct Trauma
Pathological
What is Indirect Trauma
Force transmitted in a specific fashion where there is a predictable outcome.
What is direct trauma
Force applied resulting in an unpredictable outcome e.g. RTA or a fall
What is a pathological fracture?
When the animal has an underlying bony or systematic disease which causes abnormal bone.
What are 3 ways a fracture may be classified?
Open/Closed
Complete/Incomplete
Shape of fracture
Which fracture shapes are classed as complete?
Simple Transverse
Simple Oblique
Simple Spiral
Comminuted
Avulsion
Segmented
Compression
Which fracture shapes are classed as incomplete?
Greenstick
Fissure
What force results in a greenstick fracture?
Bending
Is a fissure fracture a result of indirect or direct trauma?
Direct
What force results in transverse fracture?
Bending
What force results in oblique fracture?
Bending or Axial Compression
What force results in spiral fracture?
Override or Rotation
What causes communated fractures?
High energy trauma (direct)
Why may an avulsion fracture occur?
Muscular contraction that is stronger than the forces holding the bone together occurs e.g. a fall or pull.
What steps would you take when dealing with an open fracture?
KY Jelly
Clip the fur
Lavage
Sterile wound dressing
Doughnut bandage (relieves pressure)
State 5 principles of fracture repair
Restore bone continuity
Restore bone length
Restore functional shape of bone
Maintain freely moveable joints
Maintain normal soft tissue function
What are the 4 steps to take to ensure fracture repair
Sufficient reconstruction of normal form
Immobilisation of fragments until healing
Mobilisation of joints to prevent joint stiffness and muscle atrophy
Rehabilitation
What is a closed reduction of a fracture?
Realignment of bones without surgery with use of a splint or dressing support.
What is an open reduction of a fracture?
Surgical fixation where internal fixation is needed
What are the 3 requirements of a fracture so it can heal
Reduction of space between fragments
Immobilisation in correct alignment until clinical union
Preservation of blood supply
What is primary healing?
Direct healing where there is little to no space at fracture sites after applying internal fixation. Little or no bridging callus visible on radiographs.
What is secondary healing?
Healing via production of callus which relies on stability and viable biological tissue. (Casts and splints)
What are the four stages of bone healing?
Inflammation
Proliferative
Maturation
Remodelling
What occurs at the inflammatory stage?
Haemorrhage for 6-8 hours until haematoma forms
Vasodilation to reduce blood flow
Oedema forms
Oestocytes deprived of nutrition and die
Ends of fracture sites turn nectrotic and die
Inflammatory cells migrate to area and phagocytosis removes nectrotic tissue.
What occurs at the proliferative stage?
Haematoma is organised and stem cells invade
Granulation tissue and cartilage forms where haematoma was
Blood vessels grow down peristeum and medulla
Soft callus formed and appears 4-5 days post fracture (not seen on xray until 10-12 days post fracture)
What happens at maturation phase?
Hard callus is formed by fibrous tissue, cartilage and immature bone
High proportion of osteocytes
When callus envelopes bone ends- stability
Fibrous tissue replaced by cartilage and bone and clinical union occurs at 12-16 weeks.
What is the remodelling phase?
Initial soft callus and extra bone removed by scavenger cells
Woven bone replaced with stronger lamellar bone
Stress on bone means e+ on convex surface (osteoclastic activity) and e- on concave (osteoblastic activity)
What are 3 problems that can occur during fracture repair
Non Union (surgical intervention),
Delayed Union,
Malunion (abnormal alignment)
What negative effect could internal fixations have on an animal?
Atrophy, joint stiffness, tissue adhesion to fixture, movement of fixture
State 4 factors which may influence the rate of healing
Age, Damage to soft tissue (more likely to become infected due to reduced blood supply), Osteomyelitis (inflammation) and systemic illness
Which fracture heals faster oblique or transverse?
Oblique due to the larger surface area to promote tissue regrowth.
State 5 main functions of the skeleton
Support for soft cells and tissues
Attachments for muscles
Protection of delicate organs
Haemopoeisis- maturation of blood cells
Reservoir/Storage for minerals-calcium