Week 9 - Lesson 1 (Part 4) Flashcards
What do perforators contain?
Valves that may become incompetent
What do perforators provide?
An anastomosis between deep and superficial systems
What do perforators drain?
Superficial blood into deep veins
Where are perforators more numerous?
In the lower leg
- has more valves
What do perforators maintain?
Correct direction of flow
What can larger perforators cause?
Varicosities
- eg) Hunter perforators
What are 5 characteristics of venous flow?
- Spontaneity
- Phasicity
- Augmentation
- Competence of valves
- Absence of pulsatility
What are used to evaluate DVT, SVT and incompetent valves? (3)
- Compression images
- Colour
- Duplex
What modality is the gold standard for imaging the veins?
US
What are 9 sonographic features of normal veins?
- Thin (invisible) wall
- Smooth wall
- Anechoic lumen
- Compressible
- Unidirectional flow toward the heart
- Flow augmentation with distal compression
- Spontaneous flow
- Phasic flow
- Flow ceases with valsalva maneuver
Where does spontaneous flow occur?
In veins closest to the heart
Where is spontaneous flow less frequently seen in?
The popliteal vein
Where is spontaneous flow not seen in?
Calf veins
Where is pressure in veins the lowest?
The furthest away from the heart
What has effects on the venous pressure? (4)
- Augmentation
- Valsalva maneuver
- Pumping the calf muscle
- Respiration
What kind of blood flow occurs in the lower extremities?
Phasic with respiration
What happens to blood flow during inspiration?
It ceases
What happens to blood flow during expiration?
Augments
- increases
What could pulsatility of flow be caused by? (2)
- Right sided heart failure
- The closeness of the veins to the heart
- eg) internal jugular vein flow
What happens to the diaphragm during inhalation?
It descends
What happens to the blood flow during inhalation for lower extremities?
Its impeded
- delayed
Why is the blood flow during inhalation for lower extremities impeded?
Due to the increase in intraabdominal pressure
What happens to the diaphragm during exhalation?
The diaphragm rises
Why does the diaphragm rise during exhalation?
Because intra-abdominal pressure decreases
