9/17 Posterior Leg Flashcards
Talus refer to which part of the foot?
posterior process - medial and lateral tubercle and groove for flexor hallucis longus tendon
which is the largest bone in the foot?
Largest foot bone that articulates with:
– superiorly=____
– anteriorly=____
talus
cuboid
Sustentaculum tali (L., support of the talus)
shelf-likeprojection that supports talus and provides groove for flexor hallucis longus
Navicular
Articulates with:
– posteriorly=_____ head
– anteriorly=3______
– laterally=_____
talus
cuneiforms
cuboid
Navicular tuberosity:
– tibialis posterior attachment
for the Dynamic Arch, what are the two types of supports?
dynamic (muscle) and passive (ligament)
Crural Fascia
Thick septa
- anterior
- lateral
- posterior
anterior/posterior/medial
Posterior (Flexor; Calf) Compartment, there are two subgroups: superficial and deep posterior compartments
- superficial posterior group:
- gastrocnemius
- soleus – triceps surae
- plantaris
- deep posterior group:
- popliteus
- flexor hallucis longus
- flexor digitorum longus
- tibialis posterior
Gastrocnemius
• Two-headed muscle that crosses the knee and ankle joints:
– medial head: • superior to medial femoral condyle • medial head slightly larger (extends slightly further distally)
– lateral head: • lateral aspect superior to lateral femoral condyle
– insertion: • posterior surface of calcaneus via tendo calcaneus (achilles tendon) • Plantar flexion & flexes leg at knee joint
Gastrocnemius
• Lateral head may have sesamoid bone close to its proximal attachment: – fabella (L. bean; 3-5% of people)
possibly provide leverage for lateral head of gastroc. painful fabellar stress fracture may accompany total knee replacement.
Soleus
- Broad, flat multipennate (L., sandal) muscle – lies deep to gastrocnemius
- Horseshoe-shaped proximal attachments:
– soleal line of tibia – posterior head of fibula & superior 1/4 of posterior fibula
- Inserts into posterior surface of calcaneus via tendo calcaneus (achilles tendon)
- Form a tripartite muscle with the gastrocnemius known as the “triceps surae:” – forms calf prominence • Plantarflexion
Plantaris
- Small muscle – short belly and long tendon – often absent
- Attachments: – lateral end of lateral supracondylar line – long tendon runs between gastrocnemius and soleus – posterior surface of clacaneus via calcaneal tendon
- Weak plantarflexion & leg flexion
- Proposed to be a proprioceptive organ for foot position – the unusually high density of proprioceptive receptor end organs in this muscle supports this notion
Clinical Anatomy: Plantaris
- Long tendon commonly used in reconstructive surgery of hand tendons – its removal does not affect knee or ankle movements (or does it?)
- Possibility of rupture during violent ankle movements (e.g., sudden dorsiflexion of ankle joint) – common injury in basketball players, sprinters, and ballet dancers – pain may be so severe that person is unable to bare weight
Superficial Posterior Compartment Muscle Schematic
Deep Posterior Crural Compartment
- popliteus (not shown)
- flexor hallucis longus (FHL)
- flexor digitorum longus (FDL)
- tibialis posterior (TP)
Popliteus
- Thin flat triangular muscle – lies deep to plantaris – forms inferior floor of popliteal fossa
- Attachments: – lateral surface of lateral femoral condyle & lateral meniscus (insertion) – posterior tibia (superior to soleal line [origin])
- Functions: – unlocks extended leg by laterally rotating femur on a stationary tibia – also flexes leg weakly
Popliteal Fossa: Arteries
- Superior medial and Superior lateral genicular arteries – just superior to medial and lateral heads of gastrocnemius
- Inferior medial genicular artery – deep to medial head of gastrocnemius
- Inferior lateral genicular artery – deep to plantaris and superficial to popliteus
- You may see several muscular popliteal branches (don’t confuse them with geniculars)
Flexor Hallucis Longus
- Largest deep posterior muscle
- Lies deep to soleus
- Superior attachment: – inferior 2/3 of posterior fibula
- Passes inferiorly deep to flexor retinaculum
- Occupies a shallow groove on of sustentaculum tali
- Crosses deep to FDL tendon in sole of foot: – gives a tendinous slip to FDL tendon
- Tendon approaches great toe between sesamoid bones in tendons of FHB
- Distal attachment: – inserts into base of distal phalanx of great toe
- Functions: – flexes great toe – plantarflex foot at ankle joint
Flexor Digitorum Longus
- Deep to soleus & posterior to tibia
- Superior attachment: – posterior tibia (inferior to soleal line)
- Tendon passes posterior to tibialis posterior
- Course (con’t): – tendon passes diagonally in sole of foot (superficial to f.h.l. tendon ) – near middle of sole, divides into four tendons that pass to lateral four digits
- Distal attachment: – distal phalanx base of lateral four digits
- Functions: – flexes lateral four digits – plantarflex foot at ankle joint
Tibialis Posterior
- Deepest posterior crural muscle: – same plane as leg bones
- Lies between f.d.l. and f.h.l.
- Proximal attachment: – interosseous membrane – posterior tibia inferior to soleal line – posteromedial surface of fibula
- Tendon passes anterior to f.d.l.
- Distal attachment (various tarsal and metatarsal bones): – navicular tuberosity – cuneiforms – 2-4 metatarsal bases
- Functions: – inversion – plantarflexion
which three muscles fuse at the Achilles tendon?
The gastrocnemius and soleus muscles (calf muscles) unite into one band of tissue, which becomes the Achilles tendon
