Overview
This lecture covers the anatomy and clinical significance of the superficial and deep veins of the lower limb, including venous drainage, valves, varicose veins, and deep vein thrombosis (DVT).
Superficial Veins of the Lower Limb
- The dorsal venous plexus on the foot forms the great (long) saphenous vein and the small (short) saphenous vein.
- The great saphenous vein starts anterior to the medial malleolus, runs up the medial leg and thigh, and drains into the femoral vein via the saphenous opening.
- The small saphenous vein originates from the lateral foot, runs posteriorly up the calf, and drains into the popliteal vein in the popliteal fossa.
- Many variable subcutaneous veins also drain into these major superficial veins.
- Superficial veins contain valves to assist in blood return to the heart against gravity.
Deep Veins of the Lower Limb
- Deep veins accompany arteries and typically run in pairs (e.g., anterior tibial veins, posterior tibial veins, fibular veins).
- These deep veins join to form the popliteal vein behind the knee, which becomes the femoral vein above the knee.
- The femoral vein passes under the inguinal ligament to become the external iliac vein, draining into the pelvis.
- The profunda femoris vein drains deep thigh muscles, running parallel to its artery.
Connection Between Superficial and Deep Veins
- Perforating veins connect superficial veins to deep veins, allowing one-way blood flow due to valves.
- The muscular venous pump helps return blood by muscle contractions compressing veins, aided by fascia and valves.
Clinical Considerations
- Varicose veins result from valve incompetence, especially in the great and small saphenous veins, causing vein dilation and tortuosity.
- Deep vein thrombosis (DVT) is the formation of a clot in deep veins, commonly after prolonged immobility, leading to swelling, pain, and redness.
- A detached clot (embolus) can travel through the heart and lodge in pulmonary arteries, causing pulmonary embolism (potentially fatal).
Key Terms & Definitions
- Great saphenous vein — Long superficial vein running medially from foot to thigh, draining into the femoral vein.
- Small saphenous vein — Superficial vein running up the posterior calf, draining into the popliteal vein.
- Perforating veins — Veins connecting superficial and deep venous systems, containing one-way valves.
- Muscular venous pump — Muscle contraction system aiding blood return in veins.
- Varicose veins — Dilated, twisted veins due to failed venous valves.
- Deep vein thrombosis (DVT) — Blood clot in a deep vein, often in the lower limb.
- Pulmonary embolism — Blockage of pulmonary arteries by a clot, usually from DVT.
Action Items / Next Steps
- Review the arterial anatomy of the lower limb to reinforce the layout of deep veins.
- Identify the location of your own great saphenous vein below the medial malleolus.
- Read more on clinical signs and management of DVT and varicose veins.