Lower Limb Veins and Lymphatics Flashcards
What are the two types of venous return in the lower limb?
- Deep (accompanying arteries)
2. Superficial (close to limb surface)
How do you know deep veins?
follow arteries
Why are many of the deep veins not single?
many distal veins form venae comitantes
What is different between deep veins and arteries?
pass through the limb together blood flow is in the opposite direction, arterial flow is proximal to distal and venous flow is distal to proximal
What are venae comitantes?
Veins which accompany arteries as groups of smaller veins instead of a single larger vein as is more typical in organs and tissues
What are groups of venae comitatnes like?
usually in pairs or may be in groups of 3 or 4 in some instances and tend to be connected by smaller veins
Why is the arrangement of venae comitatnes good?
- vessel are intimately associated and it is believed that the pulsation of the arteries squeezes the veins helping to increase the venous return by squeezing the venous blood through the valves
- Allows warming of blood on its way back to trunk that has been cooled at extremities
What blood flow do the valves in the veins mean?
allows flow up to the heart
What is the calf pump?
- In the leg the deep veins are sandwiched between layers of calf muscles
- During walking and running contraction of these muscles squeeze the thin walled veins and push blood up towards the heart and this is the calf pump
What can prolonged immobility e.g. long plane journey lead to?
- less efficient venous return from foot and leg
- sluggish deep venous return can lead to deep vein thrombosis (DVT)
- dangerous
How can you prevent DVT? How do they work?
- wearing elastic surgical socks or stockings 2. compresses the superficial veins
- promoting more of the venous return through the deep pathway
- this in turn leads to a more vigorous deep venous return reducing the risk of thrombosis formation
Where does the long saphenous vein drain?
into femoral vein
What does the short saphenous vein drain?
into popliteal vein
What is the general pattern of superficial venous return?
- small veins in the digits and foot drain into a superficial dorsal venous network and a plantar venous network
- which at the ankle forms two large veins that run proximally up the limb these are the long saphenous vein and the short saphenous vein (they are sometimes called the great and small saphenous veins)
What is the journey of the long saphenous vein?
- passes from the foot anteriorly
- to the medial malleolus
- courses up the leg to the medial side of the knee
- passes medially and anteriorly in the thigh
- To pierce the fascia lata
- Drain into the femoral vein
What is the journey of the short saphenous vein?
- formed as it passes posteriorly to the lateral malleolus
- Continues coursing proximally on the posterior leg to the knee
- where it peirces the fascia covering the popliteal fossa
- drain into the popliteal vein
When are the superficial veins of the lower limb harvested?
venous grafts most commonly for coronary artery bypass grafts
How are superficial and deep veins connected?
by perforating veins
What are perforating veins?
have a single valve that allowed flow from superficial to deep
What happens if the valves become compromised?
results in back flow to the superficial veins causing them to swell and bulge and these visible swellings are varicose veins
What are varicose veins?
- painful
- lead to surface lesions
- may also contribute to the sluggish deep venous return that can increase the risk of DVT
What do lymphatic vessels usually run with?
runs with veins in most organs and tissues
What do popliteal nodes usually drain?
distal limb
What do inguinal nodes usually drain?
drain limb and pudendal region, peineum, anus and parts of the lower abdomen
