Leg Flashcards
Tarsal tunnel
Most structures pass between leg and foot through here, except anterior tibial artery, and ends of deep and superficial peroneal nerve which enter foot anterior to ankle
Anterior compartment of leg
Dorsiflex ankle, extend toes and invert foot
Posterior compartment of leg
Planterflex ankle, flex toes and invert foot
lateral compartment of leg
evert foot
Shaft of tibia
Borders - anterior, medial and interosseous
Surface - lateral, medial and posterior
Posterior surface marked by soleal line (an oblique line)
Has a groove for tibialis posterior tendon
Soleal line
Descends from lateral to medial side where it merges with medial border
Fibula
3 borders - anterior, posterior, interosseous
3 surfaces - lateral, posterior, medial
Has groove for peroneal longus and brevis muscles
Posterior compartment of leg - muscles
Separated into 2 groups - superficial and deep, separated by a layer of deep fascia.
All are innervated by tibial nerve
Superficial muscle in posterior compartment
gastrocnemius, soleus and plantaris
All insert into calcaneus and plantarflex the ankle joint
Gastroc and plantaris originate from distal end of femur hence can also flex the knee
Gastrocnemius
Most superficial in posterior compartment of leg
Medial head - attached to posterior aspect of distal femur just behind adductor tubercle and above articular surface of medial condyle
Lateral head - from lateral femoral condyle
In lower leg, converge with deeper soleus muscle to form calcaneal tendon
Innervated by tibial nerve (S1, S2)
Plantaris
Small muscle belly proximally and long thin tendon which descends through leg medially, between soleus and gastroc and joins calcaneal tendon
Origin - lateral supracondylar line of femur and oblique popliteal ligament of knee
Tibial nerve S1-S2
Soleus
Origin - soleal line and medial border of tibia (originates from tibia, fibula and tendinous ligament)
Insertion - calcaneal tendon to posterior surface of calcaneus
Deep posterior compartment of leg
popliteus, flexor hallucis longus, flexor digitorum longus and tibialis posterior
Popliteus acts on knee whilst the others on foot
Popliteus
Smallest and most superior of deep posterior comp
Unlocks extended knee at initiation of flexion and stabilizes knee by resisting external rotation of tibia on femur
Origin - lateral femoral condyle
Insertion - posterior surface of tibia
Forms part of floor of popliteal fossa
Tibial nerve L4-S1
Flexor hallucis longus
Most lateral side in posterior comp
Origin - lower 2/3 of posterior surface of fibula and adjacent interosseous membrane
Insertion - plantar surface of great toe on medial side of foot
Tibial nerve S2-S3
Flexes great toe
Flexor digitorum longus
Origin - medial side of posterior surface of tibia
Insertion - plantar surface of base of distal phalanges of lateral 4 toes
Tibial nerve S2-S3
Flexes lateral 4 toes
Forms tendon which crosses posterior (superficial) to tendon of tibialis posterior near ankle joint. Crosses inferior (superficial) to FHL to reach medial side of foot then divides into 4 tendons
Tibialis posterior
Origin - posterior surface of interosseous membrane and adjacent regions of tibia and fibula
Insertion - tuberosity of navicular and adjacent region of medial cuneiform
Lies in between and overlapped by FDL and FHL
Tendon of TP lies medial to tendon of FDL in groove on posterior surface of medial malleolus.
Inverts and plantarflex foot and supports medial arch while walking
Tibial nerve L4-L5
popliteal artery
passes into posterior compartment between gastroc (superficial) and popliteus (deep)
It passes under tendinous arch formed between fibular and tibial heads of soleus as it continues inferiorly
Enters deep compartment and divides into anterior tibial and posterior tibial artery.
Branches into 2 large sural arteries in popliteal fossa to supply gastroc, plantaris and soleus.
anterior tibial artery
passes forward through aperture in upper part of interosseous membrane and supplies anterior compartment. Continues inferiorly onto dorsal aspect of foot
posterior tibial artery
supplies posterior and lateral compartment and continues to sole of foot
Descends through deep posterior compartment on superficial surfaces of TP and FDL, passes through tarsal tunnel behind medial malleolus and into sole of foot
Branches of posterior tibial artery
Circumflex peroneal artery - passes laterally through soleus and around neck of fibula to connect to anastomotic network around knee
Peroneal artery - parallels course of tibial artery but runs in lateral compartment
Tibial nerve
passes under tendinous arch formed between fibular and tibial heads of soleus, goes through deep posterior compartment with posterior tibial vessels
enters ankle through tarsal tunnel behind medial malleolus and supply most intrinsic muscles and skin
branch of tibial nerve in leg
Branches that supply all muscles in posterior leg
Two cutaneous - sural nerve and medial calcaneal nerve
Sural nerve
originates high in leg between two heads of gastrocnemius. Descends superficial to belly of gastroc and penetrates deep fascia in middle of leg where it is joined by sural communicating branch from common peroneal nerve.
Passes down leg around lateral malleolus into the foot
Supplies lower posterolateral surface
Medial calcaneal nerve
Descends on medial side of heel
Innervates skin on medial surface and sole of heel
Muscle in lateral compartment
Peroneus brevis and longus
Both innervated by superficial peroneal nerve
Peroneus longus
Arises in lateral compartment of leg but its tendon crosses under foot to attach to bones on medial side
Origin: upper lateral surface of fibula
Attachment: undersurface of distal end of medial cuneiform and base of metatarsal I
Distally, tendon of peroneus longus passes posterior to lateral malleolus
Route of common peroneal nerve
From popliteal fossa, follows medial margin of biceps femoris over lateral head of gastroc and toward tibula
Here branches into 2 cutaneous branches - sural communicating (combines with sural nerve) and lateral sural cutaneous nerve (upper lateral leg)
Common peroneal nerve passes anteriorly around fibular neck between attachment of peroneus longus to fibular head and shaft
Peroneus brevis
deep to peroneus longus
Origin: lateral 2/3rds of lateral surface of fibular shaft
Insertion: lateral tubercle at bae of metatarsal V
Tendon of peroneus brevis passes behind lateral malleolus
Common peroneal nerve
Branches into superficial peroneal nerve and deep peroneal nerve
Superficial peroneal nerve
Descends in lateral compartment deep to peroneus longus to innervate peroneus longus and brevis
Enters foot and divides into medial and lateral branches which supply dorsal areas of foot and toes except
- web space between great and second toe (deep peroneal nerve)
- lateral side of little toe (sural nerve)
Deep peroneal nerve
passes anteromedially through intermuscular septum into anterior compartment of leg which it supplies
Muscles in anterior compartment
tibialis anterior, EHL, EDL and peroneus tertius
Deep peroneal nerve
Tibialis anterior
most anterior and medial of the muscles in anterior compartment
Origin: lateral surface of tibia
Insertion: medial cuneiform and metatarsal I
Dorsiflex ankle, inverts foot and supports medial arch during walking
EHL
lies next to and partly overlapped by tibialis anterior.
tendon appears between tibialis anterior (medial) and EDL (lateral) in lower half of leg and into foot.
Inserts on upper surface of base of distal phalanx.
EDL
Most posterior and lateral of muscles in anterior compartment.
Origin: lateral to and above origin of EHL
Peroneus tertius
Originates from below origin of EDL.
Tendon descends into foot with tendon of EDL.
On dorsal aspect of foot, deviates laterally to insert onto base of metatarsal V
Assists in dorsiflexion and eversion of foot.
Anterior tibial artery
Distal leg, lies in between tendons of tibialis anterior and EHL.
Leaves leg by passing anteriorly to distal end of tibia and continues as dorsalis pedis
Distally gives rise to anteiror medial malleolar and anterior lateral malleolar artery
Deep peroneal nerve
Originates in lateral compartment, passes anteromedially through intermuscular septum and then passes deep to EDL.
At anterior interosseous membrane meets and descends with anterior tibial artery
Inervates all muscles in anterior compartment, EDB, first 2 dorsal interossei and skin between great and second toes
