Wet Lab 8 - Blood Supply To And Drainge From The Lower Limb Flashcards
How to name and understand blood supply
Since most named arteries are accompanied by a vein which has the same name and runs with it, we focus on naming and understanding the location and branching of the arteries and the venous pattern is similar
What do we need to know about blood supply features
- name of each artery and vein
- the location of each artery
- where each artery arises, and where it ends (branches)
- the anatomoses (joining) of arteries
- important locations where we can feel the pulse of an artery
What does an artery close to another structure do?
It tends to supply blood to that structure
What is an anastomosis?
It is where one artery joins another
What takes place due to anastomosis ?
A blood cell can take one of two pathways
Where are most anatomoses found ?
Around joints
Why are anatomoses mostly foudn around joints ?
This is functionally because the joint might be moved into a position where the main artery is occluded (blocked) as it is folded back on itself, and the blood needs another pathway to continue to flow to more distal body parts
What is the main arty of the knee ?
The popliteal artery, it passes behind the knee
What happens to the popliteal artery when the knee is fully flexed?
It might become occluded. Therefore, blood is shunted around the knee through much smaller but anatomising arteries called genicular (bend for the knee) arteries
Are genciular arteries easy or hard to identify on prosecutions ?
Hard
What is an artery of the hip joint region ?
Obturator artery
What does the Obturator artery run ?
A branch of the Obturator artery (the acetabular branch) travels within the ligamentum teres to enter the head of the femur, which relies on the integrity of this artery for its blood supply
What are other arteries of the femur ?
Medial and lateral circumflex femoral arteries
Where do the femoral arteries enter?
Elsewhere
What does the femoral artery supply blood to?
Femoral neck and distal head
What does the femoral artery cross and enter ?
It crosses dept to the Inguinal ligament and it enters the femoral triangle
What does the end of bones have?
Very rich blood supply and many holes for the entrance of arteries as the red bone marrow is found there with the spongy bone
What is manufactured in the “spongy” bone
Blood cells
What is noticeable on most long bones ?
A nutrient foramen in their shaft where a branch of a named artery called the nutrient artery enters the blood to supply it with blood
What is a characteristic of bone tissue?
It is highly vascular
What are the important pulse points?
- femoral artery
- popliteal artery
- posterior tibial
- dorsalis pedis
Where can an artery best be felt ?
Where there is something hard behind it, so when you push on the artery, it doesn’t easily deflect backwards however, becomes more noticeable
What is the femoral artery pushed onto ?
It’s pushed onto pectineus/ilopsoas and the superior pubic ramus
What is the popliteal artery pushed onto
The popliteal fossa
What is the posterior Tibialis artery pushed onto ?
It is pushed onto the TDH tendons and the tibia
What is the dorsalis pedis artery pushed onto?
The talus or navicular
What are deep nerves
They are the ones that run with the same-named arteries
What are superficial nerves ?
They are those that run by themselves in the superficial fascia. Only a few of these are named in the lower limb
How to determine if a person has a femoral artery but not a popliteal artery pulse ?
How to determine if a person has a popliteal artery pulse but not a posterior tibial artery pulse ?
How to determine if a person has a posterior tibial artery pulse but not a dorsalis pedis artery pulse ?
How to determine if a person has a dorsalis pedis artery pulse but not a posterioir tibial artery pulse ?
What is the actions/function of veins?
They return blood to the heart, having collected blood from the capillary bed in tissue
Is there much blood pressure behind veins?
No, there is little blood pressure behind them, so some other mechanisms are required for the return of blood to the heart, especially upwards against gravity
What are venae comitantes
They are the vein or several veins running with each deep artery. They accompany their artery
Why are venae comitanes called deep?
Because they are beneath the deep fascia - the sleeve of collagenous tissue that wraps around all muscles
Why are the venae comitanes wrapped together with their artery ?
So that when the artery pulses (Which is the pressure wave from the heart’s systole), it briefly bulges outwards and empties the veins
Why do veins have valves in them?
They open to let blood through in the direction towards the heart, but when the blood tries to flow backwards (usually downwards in the lower limb), the slightly higher blood pressure closes the valve and stops this back flow
What helps venous return ?
The beating heart with the presence of the vascular sheath and valves
What is the muscle action of deep veins?
They are often compressed/wringed out when the muscles between which they contract. When the muscles relax, the veins refill. Together, this nucleus action and the valves form what is called a “muscle pump.’
What is an example of a muscle pump ?
The gastrocnemius and soleus which rhythmically/sequentially contract and relax during walking or as the heel raises.
What is this action of the gastrocnemius-soleus muscle pump during contraction?
When the muscle contracts, they bulge and compress the vein running between them. This empties the veins. The vein also stops the blood from flowing down which results in the blood being forced upwards towards the heart (due to the presence of valves)
What is this action of the gastrocnemius-soleus muscle pump during relxation ?
When the muscles relax, the vein can refill from below
What are the superficial veins
They are a set of veins in the superficial fascia
Where is the superficial fascia ?
It is between the skin and collagenous deep fascia
What does the superficial fascia contain ?
It contains adipose tissue (Fat), cutaneous (sensory) nerves and the superficial veins and NO arteries
Why are superficial veins more variably arranged person to person ?
Due to the more haphazard (individually variable) nature of venous development.
Are there many superficial veins ?
Yes, there are many but only several are named
What are the superficial veins in the lower limb that we need to know ?
- dorsal venous arch
- great saphenous vein
- small saphenous vein
What are perforating veins ?
They are the short veins that join and form many connections between between the superficial and deep veins
Why are they called perforating veins?
They perforate/pierce the deep fascia
What does superficial and deep veins do?
They anastomose (when a vein becomes another vein) and they often have a valve near their junction
