Tendons Flashcards
What is a bursae (4marks )
Tough connective tissue sacs
Contains synovial fluid
Placed under areas of pressure
Mainly under tendons near their insertions
What are the 4 types of collagen
Type 1 -bone
Type 2 -cartilage/tendon insertion
Type 3- endotenon ( connective tissue which surrounds the primary, secondary and tertiary fibre bundles)
Type 4- basement membrane
Why does hysteresis damage tenocytes
Because it generates heat which kills the tenocytes
What is a retinaculum
Is a band of thickened deep fascia that surrounds tendons, which holds them in place. It’s not part of any muscles but there to stabilise tendons
Eg. Holding the SDFT in place which runs down the hind limb and attaches to the calcaneus
What are tendon/ligament molecular components (3 marks )
Water -65% wet weight
Collagen - 30% wet weight
Non collagenous proteoglycans - 5% wet weight
Where are tendon sheaths found and how is it nourished (3 marks )
Present where tendons cross joints
Synovial fluid is secreted to lubricants the tendons over joints
Blood supply in sheathed tendons is carried by the mesotenon where the sheath folds inwards
Difference between elastic and positional tendons (5 marks )
Elastic tendons - used during locomotion for elastic recoil and energy transfer
Positional tendons - are stuffed and less elastic to maintain posture and limb position
Both used to absorb landing shock
3 stages of tendon healing
Inflammation
Proliferation
Remodelling
Compare and contract tendons and ligaments
Tendon- muscle to bone
Ligaments - bone to bone
Tendons used for transfer of energy from muscle to insertion point
Ligaments - to provide support to joints preventing excessive movement
How does the structure of tendons relate to biomechanics
Plays important part in locomotion
Elastic band springs back with no input energy
Flexor tendons in distal limb in weight bearing store energy when stretched. Release of elastic energy lifts food without further energetic input
How does the structure of ligaments relate to biomechanics
Some have high elastin content- can be strained to 30%
Extreme in the nuchal ligament with 70% of elastin allowing high strains
Usual strain is 5-7% fails at 12-15%
Critically compare intrinsic and extrinsic tendon healing
Extrinsic
- fibroblast and inflammatory cells move from external tissues sources to invade healing site and initiate.
- they later promote repair and regeneration
- this process includes the initial formation of adhesions and requires a well established vascular network
Intrinsic
- cells form the endotendon and epitendon migrate and proliferate into the injury site
- they establish an extra cellular matrix and an internal neovascualr network
- begins after the extrinsic healing and responsible for reorganisation of collagen fibres and maintenance of fibrillation continuity
Movement in rehab improves fluid flow = improve healing and prevent scaring when laying down new collagen fibres
If a tendon is re injured where is the new injury most like to occur
At the boundary of the healthy and scarred tendon
Stress concentration at the healthy scar boundary
Why do tendons in sheaths heal more slowly than those without a sheath
Blood supply to the tendon in a sheath is more restricted
What part of the healing process can lead to reduced tendon function
Proliferation when there is disorganised collagen
