Ligaments and Tendons Flashcards
Terms: enthesis
A progressive change from ligament to bone protects against injury by allowing better stress absorption and transmission
The structural jobs vs. functional jobs of tendons and ligaments
Structural Jobs
- stabilize joints (at end range)
- guide joint motion
- prevent excessive motion
Functional Jobs
- detect rate and vectors of load via mechanoreceptors
- detect tissue damage via nocireceptors
The difference between ductile and brittle material (based on % strain to failure, be able
to recognize a stress strain curve of a ductile vs. a brittle material)
Brittle material will fail at less then 5%
Ductile material will fail past 5%
The characteristics of the creep-relaxation phenomenon
- A deformation of a viscoelastic material with time, when the load remains constant
- gradual rearrangement of collagen, proteoglycans, and water molecules
Short and long term effects of a sprain
Short term:
Hyper mobility and instability
Longterm:
- degeneration of joints
- susceptibility to further injury
Strength of ligament depends on what factors
Both bone and ligament get stronger with increase speed of loading
-the strength of the bone increases more then the strength of the ligament increases in strength so the ligament fail first
What can happen to a ligament (types of damage or diagnoses)
Postral syndrome/sprain
Tears known as Sprain
Joint instability = 2nd or 3rd degree sprain
Fibrosis= scar tissue
Effect of speed of loading on strength of a tendon or ligament
at high speed load: ligament tears 2/3 tests
1/3 of time so bone comes off but ligament is intact called a bony avulsion
at low speed load for 1 min: bone avulsion occurs
• The characteristics of physiological loading (reserve capacity, effects of repetitive
loading)
more than enough strength under normal physiological conditions, the tensile load is only about 1/3 of its strength capacity
- but high loads or repetitive loads or sustained loads can result in injury
Know the joint displacement graph for the anterior cruciate ligament
slide
what is hysteresis, how does it occur with sitting, be able to explain the graphs.
Loss of energy during a loading cycle, even when it does return to original form
-ligaments and posterior disc are placed under a sustained flexion load and after some time hysteresis and creep occurs
pg 16
Factors that affect ligaments (e.g., age, steroids, etc)
- corticosteroids inhibit collagen synthesis
- injection around ligament prevents early strenuous rehab
- time and dosage dependent
- no difference with a single injection
Aging
Pregnancy
Mobilization
Know the stress strain graph. Be able to draw, label it, recognize if given to you. Know
at what point in the graph someone might get symptoms
chart
Differences among deformation, stress, load, strain.
Deformation: A change in length in response to a load
Stress: A load can be expressed another way “stress” Stress is the load divided by the cross sectional area
Strain: The amount of deformation can be expressed another way. Strain is a change in length divided by the original length
Load: The amount of force of an object. The three most basic types of load are tensile compressive, and shear
Define the Terms: stiffness, flexibility, elasticity, plasticity
Elasticity: The ability of a substance or material to return to its original form following the removal of a deforming load
Plasticity: The property of a material to permanently deform if loaded beyond its elastic range
Stiffness: A measure of resistance offered to external loads by a material as it deforms
