9/17 Posterior Leg

Question 1

Talus refer to which part of the foot?

Answer 1

posterior process - medial and lateral tubercle and groove for flexor hallucis longus tendon

Question 2

which is the largest bone in the foot?

Largest foot bone that articulates with:

– superiorly=____
– anteriorly=____

Answer 2

talus

cuboid

Question 3

Sustentaculum tali (L., support of the talus)

Answer 3

shelf-likeprojection that supports talus and provides groove for flexor hallucis longus

Question 4

Navicular

Articulates with:

– posteriorly=_____ head

– anteriorly=3______

– laterally=_____

Answer 4

talus

cuneiforms

cuboid

Question 5

Navicular tuberosity:

– tibialis posterior attachment

Question 6

for the Dynamic Arch, what are the two types of supports?

Answer 6

dynamic (muscle) and passive (ligament)

Question 7

Crural Fascia

Thick septa

1. anterior
2. lateral
3. posterior

Question 8

anterior/posterior/medial

Answer 8

Question 9

Posterior (Flexor; Calf) Compartment, there are two subgroups: superficial and deep posterior compartments

Answer 9

1. superficial posterior group:

• gastrocnemius
• soleus – triceps surae
• plantaris

2. deep posterior group:

• popliteus
• flexor hallucis longus
• flexor digitorum longus
• tibialis posterior

Question 10

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

Answer 10

Question 11

Gastrocnemius

• Lateral head may have sesamoid bone close to its proximal attachment: – fabella (L. bean; 3-5% of people)

Answer 11

possibly provide leverage for lateral head of gastroc. painful fabellar stress fracture may accompany total knee replacement.

Question 12

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

Answer 12

Question 13

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

Answer 13

Question 14

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

Question 15

Superficial Posterior Compartment Muscle Schematic

Question 16

Deep Posterior Crural Compartment

1. popliteus (not shown)
2. flexor hallucis longus (FHL)
3. flexor digitorum longus (FDL)
4. tibialis posterior (TP)

Question 17

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

Question 18

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)

Question 19

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

Answer 19

• 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

Question 20

Flexor Digitorum Longus

• Deep to soleus & posterior to tibia
• Superior attachment: – posterior tibia (inferior to soleal line)
• Tendon passes posterior to tibialis posterior

Answer 20

• 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

Question 21

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

Answer 21

• Tendon passes anterior to f.d.l.
• Distal attachment (various tarsal and metatarsal bones): – navicular tuberosity – cuneiforms – 2-4 metatarsal bases
• Functions: – inversion – plantarflexion

Question 22

which three muscles fuse at the Achilles tendon?

Answer 22

The gastrocnemius and soleus muscles (calf muscles) unite into one band of tissue, which becomes the Achilles tendon

Question 23

Answer 23

Question 24

Answer 24

Question 25

“TOM Dick a.n. Harry”

Question 26

Posterior Compartment: Innervation

• Tibial nerve supplies all posterior compartment muscles

Question 27

Tibial Nerve

• Passes with posterior tibial vessels – deep to soleus – posterior to tibialis posterior
• Leaves posterior compartment by passing deep to flexor retinaculum between medial malleolus and calcaneus – ends by dividing into medial and lateral plantar nerves (posteroinferior to medial malleolus)

Question 28

Posterior Compartment: Blood Supply

• Posterior tibial artery:

– begins near inferior border of popliteus (deep to soleus)

– gives rise to fibular artery

– passes inferomedially on posterior surface of tibialis posterior with tibial nerve

– runs deep to flexor retinaculum

– vascularizes posterior compartment

• Ends by dividing into medial and lateral plantar arteries

Answer 28

Question 29

Fibular Artery (lateral side)

• Largest branch of posterior tibial artery
• Begins inferior to distal border of popliteus
• Descends obliquely toward fibula, usually under FHL
• Ends by piercing interosseous membrane and anastomosing with anterior lateral malleolar artery
• Vacularizes posterior and lateral comparments

Question 30

Clinical Anatomy: Posterior Tibial Artery

• Posterior tibial pulse palpated between: – posterior surface of medial malleolus – medial border of calcaneal tendon – deep to flexor retinaculum • important to have patient to relax retinaculum by inverting foot

Answer 30

• Used to examine patients with occlusive peripheral arterial disease (intermittent claudication):

– condition caused by ischemia of leg muscles due to narrowing or occlusion of leg arteries

– characterized by leg cramps and pain during walking (disappears after rest)