Posterior Leg: Part 1 Flashcards
Fascial compartments of the leg formed by
- Tibia and fibula
- Intermuscular septa
- Interosseous membrane
Anterior compartment
- Extensors of ankle (foot) and toes
- Deep fibular (peroneal) nerve
- Anterior tibial artery
Posterior compartment
- Flexors of ankle and toes
- Tibal nerve
- Posterior tibial and fibular arteries
Lateral compartment
- Evertors of ankle
- Superficial fibular nerve
- Perforating branches of anterior tibial and fibular arteries
Small saphenous vein arises from
- Dorsal venous arch (lateral marginal vein)
- Dorsal vein of 5th digit
Small saphenous vein pathway
- Posterior to lateral malleolus
- Drains into popliteal vein (not always)
- Travels with sural nerve
Majority of superficial lymph vessels (in superficial fascia) drain into
- Vertical group of superficial inguinal nodes (great saphenous territory)
Superficial lymphatics in the small saphenous territory (posterior, lateral leg and foot) drain into
- Popliteal nodes
Deep lymphatics (deep to deep fascia)
- Lymph vessels travel with blood vessels and drain into:
- Popliteal nodes (deep tissues of leg and foot)
- Popliteal nodes drain into deep inguinal nodes
Tibial nerve (L4-S3) gives off
- Medial sural cutaneous (S1,2)
Common fibular (L4-S2) gives off
- Lateral sural cutaneous (L5-S2)
- Sural (fibular or peroneal) communicating branch (S1,2)
Lateral sural cutaneous (L5-S2) supplies
- Superior lateral leg
Sural nerve (S1,2) is formed by
- Fibular communicating branch joins medial sural cutaneous
Sural nerve (S1,2) pathway
- Runs close to small saphenous vein
- Passes around posterior border of lateral malleolus than inferior to it
Sural nerve (S1,2) supplies
- Distal posterior and lateral leg
- Lateral calcaneus (lateral calcaneal branches)
- Lateral side of foot and lateral side of 5th digits (lateral dorsal cutaneous nerve)
Posterior compartment of leg (posterior crural compartment)
- 2 subcompartments
- Divided by deep transverse intermuscular septum of the leg (deep transverse crural intermuscular septum)
- Attach medial margin of tibia and posterior border of fibula
Superficial compartment supplied by
- Sural arteries
Deep compartment supplied by
- Posterior tibial arteries
- More tightly surrounded by fascia
- More susceptible to compartment syndrome
Functions of posterior compartment muscles
- Tibial nerve supplies the muscle
- Plantarflexion (flexors)
- Inversion
- Toe flexion
Tendons of posterior compartment muscles pathway
- Pass and insert medial to subtalar joint
- Can cause supination of the subtalar joint
Primary functions of superficial muscles of the posterior compartment
- Powerful plantarflexors
Muscles of the superficial posterior compartment
- Gastrocnemius
- Soleus
- Plantaris
- Calcaneal tendon (Achilles)
Gastrocnemius
- 2 heads originate from femoral condyles
- Important in rapid, power movement
Gastrocnemius medial head origin
- Posterior aspect of medial femoral condyle
- Inferior aspect of medial supracondylar line
- Crural fascia
Gastrocnemius lateral head origin
- Posterior aspect of lateral femoral condyle
- Inferior aspect of lateral supracondylar line
- Crural fascia
Gastrocnemius (both heads) insertion
- The 2 heads fuse and anchor to the gastrocnemius aponeurosis
- The aponeurosis will join with superficial surface of soleus aponeurosis
- Middle 1/3 of posterior surface of calcaneus (via calcaneal tendon/Achilles tendon/tendo calcaneus)
Gastrocnemius innervation
- Tibial nerve
Gastrocnemius blood supply
- Medial and lateral sural arteries
- End arteries
Gastrocnemius function
- Plantarflexion foot (ankle)
- Flexion of the leg
- Subtalar supination
Flabella
- Sesamoid bone in lateral head of gastrocnemius
- ~10-30% of population
- Studies have shown that it is getting more prevalant
Soleus
- Broad/flat muscle
- Forms soleal arch (tibial nerve/popliteal artery passes deep)
- Continuously active
Soleus origin
- Middle 1/3 of tibia medial border
- Soleal line
- Tendinous arch
- Posterior aspect of fibular head
- Proximal 1/3 of fibula
Soleus insertion
- Joins with gastrocnemius
- Same as gastrocnemius
Soleus innervation
- Tibial nerve
Soleus blood supply
- Sural arteries
- Fibular artery
- Posterior tibial artery
Soleus function
- Plantarflex foot (ankle)
Triceps surae (gastroc-soleus group)
- Gastrocneumius + Soleus
- 3 heads (share insertion)
- Powerful plantarflexors
Plantaris
- Small muscle
- Long tendon between gastrocnemius and soleus
Plantaris origin
- Distal aspect lateral supracondylar line
- Travels inferomedially
Plantaris insertion
- Medial aspect of middle 1/3 of posterior calcaneus
- Medial to achilles
Plantaris innervation
- Tibial nurve
Plantaris blood supply
- Sural artery
Plantaris function
- Plantarflexion
- Knee flexion
- Probably proprioceptive function
- Used in reconstructive surgery
Gastrocnemius aponeurosis fuses with
- Soleal aponeurosis
Calcaneal tendon (Achilles) inserts into
- Posterior calcaneus
- Twists inward as it descends toward calcaneus
- Clockwise left, counterclockwise right
Gastrocnemius tendon fibers
- Lateral at their insertion
Soleus tendon fibers
- Medial at the insertion
Calcaneal tendon (Achilles) has no tendon sheath
- Has a paratenon
- Contains numerous small vessels that supply the tendon
- Branches from fibular and posterior tibial artery
Watershed area of calcaneal tendon (Achilles)
- Located 2-6 cm above insertion
Retrocalcaneal bursa
- Superficial: between tendon and skin
- Deep: between tendon and trigonum achilleum
