Principles of Tendon and Ligament Biology Flashcards
What are tendons and liagements
Dense, fibrous connective tissue
What is the role of Type 1 collagen
It provides high tensile strength
What does the fact that tendons and liagements are viscoelastic mean
They respond a different way depending on the force/ speed of movement
What does the crimping in tendon tissue mean
You are able to apply a lot of stress to a tendon without it rupturing
In tendons and ligaments what provides a failsafe mechanism
Fasciles
What does the fact that tendons and ligaments are not passive structures mean
They respond to mechanical loading and exercise
What are living cells in tendons called
Fibrblasts
What do fibroblasts do
Look after and produce ECM
How do fibroblasts communcate
Via gap junctions
How to fibroblasts detect and respond to mechanical loading
By increasing the amount of collagen
Why do athletes have larger tendons
Because of their constant, long-term commitment
What happens to tendons in cases of immobalisation
They become thinner and weaker. In long term recovery form casting it is essential in the beginning to improve motility before exerting force in order to regain controlled passive movement.
Why are tendons an essential component of the musculoskeletal system
They transfer force from muscle to bone to generate movement
Where do tendons attach
They extend from myotendinous junction (MTJ) to enthesis (osteotendinous junction)
What do tendons do
Enable the muscle bulk to be distant from the site of action, reduce bulk and occupy narrow spaces
What kind of movement do tendons enable
Proportionate movement
What does tendons reinforcing/ replacing joint capsules do
Help to stabilise joints in the shoulder and proximal interphalangeal joints
What does the fact that tendons have an elastic nature mean
They can harness energy in locomotion and add this energy to subsequent action meaning that movement is economical
Where do ligaments attach
Bone to bone (one enthesis to another)
What do ligaments do
Guide and limit joint movements by limiting allowable movements and prohibiting unwanted movements
What can ligaments be
Separate, accessory or capsule thickenings. Sometimes ligaments become part of the joint capsule
Where have proproception-mechanoreceptors been identified
In the shoulder, knee and ankle joints (and overlying cutaneous layer)
What hold tendons in place
Retinaculae
What do retinacular in digits do and what happens if they rupure
Ensure the tendon runs close to the bone, if they ruprue bowstringing occurs.
What makes up myotendinous junctions and what do they do
Made up by ligaments. They transfer force from the muscle to the tendon.
What is the key feature of the end of a muscle before it attaches it connective tissue
It is high invaginated
What does invagination do
Increase the surface area for attachment
Why are myotendious junctions highly adapted to transfre force
The muscle is high invaginated before it attaches to the connective tissue
What are muscles that cross 2 joints called
Biarticular
What are muscles tears the occurs at the MTJ typical of
Eccentric contraction
What shape are flexor tendons and why
Round/oval which is characteristic of tendons in the palm of the hand to enable tendons to glide smoothly resulting in less friction
What shape are extensor tendons and why
Flattened to prevent sublaxation (means tendons go over the top of the knuckle when you make a fist and don’t fall out of place
What is present between tendons
Connective tissue
What are the clinical characteristic of chronic tendinopathy
> 3 months, pain, impaired activity and stiffness, increased tendon thickness, may lead to partial/ total rupture, tendinitis-inflammation
Histological observations during surgical interventions in chronic tendinopathy
No inflammatory cells, instead get disordered collagen and fatty deposits resulting in degeneration. During the initial stages inflammation may be present
In scans what does a healthy tendon look like
Bright white
In scans what does a pathological tendon look like
Brown and thickened or yellow due to calcification
What is used to test for a torn Achilles tendon and what means the Achilles is ruptured
The Thompson test. No movement= Achilles ruptured
Describe tendon rupture
Spontaneous rupture is most commonly observed during sporting activities, especially during eccentric contraction. Before a rupture a patient is asymptomatic. During a rupture there is pain, sudden popping, bruising and a little bleeding.
Under histological examination what do most tendons sow
Degeneration within several cm above and below the rupture
What are entheses
Attachments of tendons or ligaments to bone
What are entheses prone to
Pathology
What are examples of enthesopathies
Tennis elbow, heel spurs, Os-good Schlatters disease, spondylarthropathies
What is Os-good Schlatters disease
Inflammation at the attachment site of the tibia
What is ankylosing spondylitis
Ossification of enthesis resulting in decreased movement (back, rib expansion, neck) and effects the vertebral column as well as other regions resulting in pain and limited movement
What is the primary target organ of ankylosing spondylitis
Enthesis
Who does ankylosing spondylitis effect
Males when they are around 25 years old
What are the two types of entheses
Fibrous and fibrocartilaginous
What are fibrocartilaginous entheses
Where the tendon attaches to the end of a long bone or short bone of the hands or feet
Which type of entheses are much more prone to pathologies
Fibricartilaginous
What is the function of fibrocartilaginous entheses
They enable gradual bending meaning that the fiber isn’t focused at the tissue interface resulting in decreased fraying and dissapation of stress away from the tissue interface
What is the smooth front of a fibrocartilaginous enthesis made of and what is its function
It is a calcium front and the smooth front strengthens and prevents movement.
What does the fact that the fibrocartilaginous enthesis is high invaginated mean
`The surface area is increased and therefore a stronger attachment site is formed
What does the strength of the fibrocartilaginous enthesis mean
You are more likely for the bone attachment to break off from the rest of the bone than the fibrocartilaginous enthesis to rupture
Why does degeneration of the fibrocartilaginous enthesis occur in golfers/ tennis elbow
It is due to repeated loading
What are tendons called when they change the direction of the muscle they pull
‘wrap around regions’ or ‘gliding regions’
What do the wrap around pulleys of tendons do
Generate movement
What is an important functional adaptation that takes place in ‘wrap around regions’
The area adjacent to the bone becomes compressed and therefore cartilaginous type tissue which resists compression (tendon undergoes metaplasia- changing tissue type)
Why are tendons in the foot a common injury site in runners
Due to degeneration of tendons
