WEEK 4 - Tendons & Ligaments

Question 1

What are tendons & ligaments?

Answer 1

Dense, regular, connective tissue.

TENDONS - Muscle to Bone

LIGAMENTS - Bone to Bone

Question 2

What is function of ligament?

Answer 2

Transmit tensile forces from bone to bone. Strong (to provide stability) and Flexible (to allow joint motion / rotation).

Question 3

Describe ligament properties on function map.

Answer 3

Smaller toe region: low forces for a lot of angular changes.

Question 4

Do ligament properties / function vary in vertebral column?

Answer 4

Differences in ORM are related to HOW the vertebral column interacts and how they vary.
More flex-ext: Cervical, Lower thoracic, Lumbar
More latflex: Cervical
More Rotation: C1-2, cervical, thoracic

Question 5

Describe vertebral ligaments - Anterior & Posterior longitudinal ligaments

Answer 5

SUPERIFICAL LAYER - fibres span several layers of spinal cord
DEEP LAYER - fibres cross only Adjacent to vertebrae, attach on annulus fibrosis

Question 6

Characteristic of vertebral ligament?

Answer 6

Provide brace to prevent injury to spinal cord by LIMITING FLEX/EXT (thickest ligaments in thoracic region)
If a ligament is damaged it is mostly likely the SHORTER FIBRES

Question 7

Describe vertebral ligaments - Ligamentum Flavum

Answer 7

Thick elastic ligament that connects lamina - vertebral canal wall
Elastic but constantly under tension
- Pulls vertebrae together
- Allows spine to return to neutral after rotating / twisting
Contains large amount of elastane - 80% elastane; 20% collagen

Question 8

Ankle ligaments - most common injury?

Answer 8

Inversion ankle sprain
Due to size of ligaments on medial vs lateral
- MEDIAL: Deltoid ligaments (broad)
vs
- LATERAL: 3 separate ligaments (easier to damage)

Question 9

How can we test the mechanical properties of these ligaments?

Answer 9

Stress test:
- Anterior Draw test (ATFL)
- Talar tilt (lateral ankle ligaments)
- Eversion stress test (deltoid ligaments)

Question 10

Describe Plantar Ligaments

Answer 10

They behave like tendonds
3 arches (2 longitudinal + 1 transverse)
Function: Adapt to surfaces & dampen impact forces

Question 11

Shape of arches determined by 3 characteristics:

Answer 11

1. Arrangement of bones in the foot
2. Plantar ligaments
3. Plantar aponeurosis / fascia
   - WINDLASS MECHANISM = lifting toes on WB foot will lift arch as aponeurosis is pulled
   - Stiffens foot to allow for efficient propulsion during push-off gait (stiffness transfers forces from body to ground)

Question 12

Describe ACL

Answer 12

Frequently damaged
Resists ANTERIOR TIBIAL BAND TRANSLATION and rotational capacity of knee

2 bundles on ACL
- Non linear elongation curve - provides A LOT of motion under low joint angles, more resistance & strength

Question 13

What is the function of tendon?

Answer 13

Transmit forces from muscle to bone (joint motion)

1. They absorb, store and release energy - maximizes energy efficiency and conservation
2. Amplify power - store slow and release fast
3. Protects muscle - power attenuation, shock absorber, picks up slack

Question 14

Which tendons are the PREDOMINANT ENERGY STORING tendons?

Answer 14

1. Achilles tendon
   
   • fails at greater than 12% strain
   • in single leg hopping, contributes to 16%
     total body work
2. Patellar Tendon

Question 15

Describe energy storage tendons

Answer 15

• They have increased elasticity and fatigue resistance
  
  • most fail at 3-8%
  • Achilles tendon fails at strain GREATER THAN 12%

Question 16

What is energy buffering?

Answer 16

An injury prevention mechanism
Tendons are used to take up slack - tendon lengthens before muscles to prevent eccentric damage

Question 17

What is amplifying tendons?

Answer 17

Slow storage (tendon slowly stretches) and rapid recoil (faster dispense of energy)
Slow storage + rapid recoil = more power

Question 18

3 insertions of achilles tendon?

Answer 18

1. Lateral gastroc - straight fascicles
2. Medial gastroc - twist around before insertion
3. Soleus - twist before insertion

Question 19

Describe fascicles of Achilles tendon

Answer 19

• Spiral 90 deg during descient
  - allows elongation + elastic recoil for e release
  - MG fibres parallel
  - LG and Sol twist around before insertion = strong torsion

Pathology in Achilles is common in area of its maximum torsion (where they both spiral around)

Question 20

How to determine tendon properties (STIFFNESS)?

Answer 20

Dynamometer
Measured Achilles tendon length using contractions under ultrasound
This can measure:
1. HOW MUCH force
2. Able to plot FORCE vs LENGTH change

Question 21

Describe ITB

Answer 21

• ITB evolved for energy storage
• Stores 1 joule energy / stride in slow running
• Stores 7 joules energy / stride in fast running

Most common overuse running injuries = ITB injury