Distal Neurovasculature - Ankle & Foot Flashcards
What is the venous drainage of the lower limbs?
Superficial:
Dorsal venous arch of foot drains into saphenous veins that form the superficial venous drainage route and include:
1. Small/short: pass posterior to lateral malleolus (w/ the sural n.)
2. Great/long: pass anterior to medial malleolus (w/ the saphenous n.)
Deep:
Superficial veins located superficial of the deep fascia and drain into deep veins that pass from posterior leg as the posterior tibial then popliteal towards femoral triangle to become the femoral vein
What can the great/long saphenous vein be used for?
- Spare part for grafting procedures (CABG)
- Accessed via venous cut-down in emergencies to insert a cannula when peripheral cannulation is difficult e.g. trauma, burns or hypovolaemic shock
What is the route of the great/long saphenous vein?
- Anterior to medial malleolus
- Along posterior region of medial tibial border alongside saphenous n.
- Passes 4 finger breadth (7-10cm) posterior to the patella
- Passes through saphenous opening in a zone 1-4cm lateral and 0-3cm inferior to the pubic tubercle
- Goes deep into the femoral triangle to join the femoral vein
What is the route of the small/short saphenous vein?
- Passes from lateral foot posterior to lateral malleolus
- Ascends midline posterior leg alongside sural cutaneous n.
- Travels deep into popliteal fossa via crural fascia joining the popliteal vein
What is a varicose vein? What symptoms will the patient have? What conditions can predispose to formation of varicose veins?
Swollen and enlarged veins that usually occur on the legs and feet being blue/dark purple, lumpy, bulging or twisted in appearance. The patient may experience aching, heavy and uncomfortable legs, burning/throbbing legs, muscle cramps in leg (esp. at night), swollen feet/ankles and dry/itchy/thin skin over the area. They often run in families and in overweight/obese individuals. They are more common in females and in pregnancy.
What might be the consequence of damage to the sural nerve?
Paraesthesia or sensory loss in the calf region
What is between the gastrocnemius and soleus muscles?
Part of the deep venous drainage system: extensive venous plexus (where DVT occurs)
Why is knowledge of the deep venous system important?
Immobilised patients are at high risk of deep vein thrombosis which is why patients must mobilise soon after surgery - be suspicious if pain is reported in lower limb and make sure to look and examine limb as it will be red, swollen and hot
What might increase a persons risk of deep vein thrombosis (DVT)?
Stasis > 60 years old Overweight/obesity Smoking Dehydration Hypercoagulability
What are the 4 borders of the popliteal fossa?
Top L: Biceps femoris
Top R: Semimembranosus and semitendinosus
Bottom: Lateral and medial head of gastrocnemius
What does the tibial nerve supply?
Posterior leg and dorsal foot
What is the nerves of the lower limb?
- Superficial and lateral in popliteal fossa is the sciatic branching into common fibular and tibial n.
- Common fibular n. passes around fibula neck superficially
- Splits off into superficial fibular and deep fibular n.
- Superficial fibular n. innervates lateral leg compartment muscles and skin over most of the dorsal foot
- Deep fibular n. innervates the anterior leg compartment muscles, muscles of dorsal foot and skin between digits 1 and 2
- Tibial n. runs in anterior compartment in company of anterior tibial artery
What will occur if the lower limb nerves are damaged?
Common fibular: inability to dorsiflex causing foot-drop and high-knee, toe-heel (tap-tap) or circumduction gait
Deep fibular: foot-drop if proximally damaged
Superficial fibular: inability to prevent foot inversion
What is the thighs arterial supply?
- Femoral artery subcutaneous within femoral triangle (vulnerable in stab injury/surgery) then under sartorius through adductor hiatus into popliteal fossa
- Profunda femoris/deep femoral branch passes close to femoral neck alongside femoral shaft and passes through adductor magnus
- Popliteal artery passes through popliteal fossa close to supracondylar part of femur (vulnerable in femoral # and bleeds)
What is the leg arterial supply?
- Popliteal artery splits into anterior tibial and posterior tibial artery
- Anterior tibial artery passes deep in anterior leg compartment anterior to interosseous membrane running alongside deep fibular n.
- Anterior tibial artery passes onto dorsal foot as dorsalis pedis artery between EDL and EHL tendon and becomes the arcuate artery
- Posterior tibial artery passes under soleal arch deep in posterior leg compartment (and also gives off a fibular artery branch supplying lateral leg)
- Posterior tibial artery passes posterior to medial malleolus in tarsal tunnel into deep plantar arch on sole of foot
What are the consequences/examination finds associated with a blockage of the femoral artery in the anterior thigh?
Limb will be cold and the patient will experience pain which gets worst upon activity and goes away with rest (intermittent claudication) so they will be able to do less activity than before
What is the tarsal tunnel?
A flexor retinaculum covered canal between the calcaneus bone and medial malleolus that contains (from anterior to posterior):
- Tibialis posterior
- Flexor digitorum
- Posterior tibial artery
- Vein
- Tibial n.
- FHL
What can happen to tendons if they wear excessively on the bone they pass around? What symptoms will the patient have? What could consequently happen to the arches of the feet?
The tendons can rupture under excessive wear and tear causing pain and collapsed and flattened arches of the feet
