L9 - Leg

Question 1

what are the two bones of the leg?

Answer 1

tibia and fibula

Question 2

describe the tibia

Answer 2

• most common long bone to be fractured
• relatively poor blood supply
• anteromedial surface is bare (available for bone grafts)
• soleal (oblique) line on posterior surface

Question 3

describe the fibula

Answer 3

• lateral malleolus important in ankle stability

- site for muscle attachment

Question 4

describe the anterior proximal end of the tibia

Answer 4

• medial and lateral condyles
• tuberosity
• tubercles of intercondylar eminence

Question 5

describe the posterior proximal end of the tibia

Answer 5

• medial and lateral condyles
• tubercles of intercondylar eminence
• articular facet for fibula (on inferior surface of lateral condyle)
• soleal line (shallow rough ridge curving down from lateral condyle)

Question 6

describe the anterior distal end of the tibia

Answer 6

medial malleolus

Question 7

describe the lateral distal end of the tibia

Answer 7

• fibular notch

- soleal line: shallow rough ridge curving down from lateral condyle)

Question 8

describe the fibula, its function, and something important

Answer 8

• lies lateral to the tibia
• function: involved in ankle joint; muscle attachment
• both tibia and fibula have interosseous borders

Question 9

describe the proximal and distal ends of the fibula

Answer 9

proximal: head, apex (styloid process), articular surface (facet) for lateral condyle of tibia

lateral malleolus (w articular surface for talus)

Question 10

describe the crural fascia

Answer 10

• its continuous with fascia latae
• attachment to anterior and medial borders of tibia:
  = continuous with periosteum
  = leaves bare area

Question 11

what retinacula are formed by the fascia?

Answer 11

• superior (extensor)
• inferior (extensor)
• flexor retinaculum
• superior/ inferior peroneal retinacula

Question 12

describe the superior (extensor) retinaculum

Answer 12

• proximal to malleoli

- binds tendons in anterior crural compartment

Question 13

describe the inferior retinaculum

Answer 13

Y shaped

Question 14

EXAM: describe the flexor retinaculum

Answer 14

• binds tendons of the deep posterior compartment

Question 15

describe the superior/ inferior peroneal retinacula

Answer 15

bind tendons of lateral crural compartment

Question 16

describe the superficial posterior compoartment: cutaneous nerves

Answer 16

• lateral sural cutaneous nerve (from common nerve)

- medial sural cutaneous: from tibial nerve

Question 17

what does the sural nerve run with?

Answer 17

the lesser saphenous vein

Question 18

what are the muscles of the superficial posterior compartment muscles?

Answer 18

• gastrocnemius
• plantaris
• soleous
• triceps surae
• common insertion

Question 19

describe the gastrocnemius

Answer 19

• crosses both knee and ankle joint
• two heads form inferior boundaries of the popliteal fossa
• lateral head may have a sesamoid bone: fabella

Question 20

describe the plantaris

Answer 20

• may be absent

- tendon may be used for hand surgery

Question 21

describe the soleus

Answer 21

• broad multipennate muscle

- unijoint muscle

Question 22

describe the triceps surae

Answer 22

• soleus + two heads of gastrocnemius

Question 23

describe the common insertion

Answer 23

• calcaneus via tendo calcaneus (achilles tendon)

Question 24

what nerve supplies the superficial posterior compartment?

Answer 24

tibial nerve

Question 25

describe the tibial nerve

Answer 25

- supplies all muscles in posterior compartment - divides into medial and lateral plantar nerves inferior and posterior to medial malleolus - gives off medial sural cutaneous nerve - joins with communicating branch of common peroneal (fibular) nerve to form: sural nerve: cutaneous

Question 26

describe the superficial posterior compartment blood supply

Answer 26

- posterior tibial artery | - peroneal (fibular) artery

Question 27

describe the posterior tibial artery

Answer 27

- largest branch of popliteal artery | - divides into medial and lateral plantar arteries deep to origin of abductor hallucis muscle

Question 28

describe the peroneal (fibular) artery

Answer 28

- most important branch of posterior tibial artery - supplies lateral compartment and popliteus muscles - supplies other muscles in posterior compartment

Question 29

what are the muscles of the deep posterior compartment of the leg?

Answer 29

- popliteus - flexor digitorum longus - flexor hallucis longus - tibialis posterior

Question 30

describe the popliteus

Answer 30

- lies in floor of popliteal fossa | - flexes and rotates knee**

Question 31

describe the flexor digitorum longus

Answer 31

- tendon passes posterior to medial malleolus and to tendon of tibialis posterior - plantarflexes foot at ankle joint

Question 32

describe the flexor hallucis longus

Answer 32

- tendon occupies groove on posterior surface of talus - continuous w groove on plantar surface of sustentaculum tali - tendon passes posterior to medial malleolus - tendon passes between two sesamoid bones - push-off muscle for walking, running, jumping

Question 33

describe the tibialis posterior

Answer 33

- functions in plantar flexion and foot inversion | - helps to maintain medal longitudinal arch

Question 34

what is the nerve supply and the blood supply to the deep posterior compartment

Answer 34

- tibialis nerve | - posterior tibial artery

Question 35

what are the muscles of the anterior compartment of the leg?

Answer 35

- tibialis anterior - extensor digitorum longus - peroneus (fibularis) tertius - extensor hallucis longus

Question 36

describe the tibialis anterior

Answer 36

- lateral to crest of tibia - foot dorsiflexion and inversion - L4-L5 - paralysis results in foot drop

Question 37

describe the extensor digitorum longus

Answer 37

- four tendons of insertion - each tendon inserts on an extensor expansion similar to arrangement in hand - toe extension at MTP and also dorsiflexion

Question 38

describe the peroneus tertius

Answer 38

- part of extensor digitorum longus - sometimes missing - foot dorsiflexion and eversion

Question 39

what is the function of the anterior compartment?

Answer 39

- toe extension | - ankle dorsiflexion

Question 40

what is the innervation of the anterior compartment? describe it

Answer 40

Deep peroneal (fibular) nerve - L4-L5 to tibialis anterior - L5-S1 for remaining muscles - runs deep to extensor digitorum longus - accompanies anterior tibial artery between extensor hallucis longus and tibialis anterior muscles

Question 41

what is the blood supply to the anterior compartment?

Answer 41

anterior tibial artery - smaller terminal branch of popliteal artery - begins at inferior border of popliteus muscle - becomes dorsalis pedis artery at ankle joint

Question 42

what are the muscles of the lateral compartment of the leg?

Answer 42

- peroneus (fibularis) longus | - peroneus brevis

Question 43

describe PL

Answer 43

- more superficial of the two - easily palpated - its tendon uses lateral malleolus as a pulley - tendon crosses sole of foot and inserts on first metatarsus and cuneiform - helps to maintain transverse and longitudinal arches of the foot

Question 44

describe PB

Answer 44

- deep to peroneus longus - inserts on lateral tuberosity - functions in plantar flexion and foot eversion

Question 45

what is the nerve supply to the lateral compartment of the leg?

Answer 45

- superficial peroneol (fibular) nerve: = deep to peroneus longus = inserts on lateral tuberosity

Question 46

blood supply to the lateral compart?

Answer 46

- no major arteries in lat comp - muscular branches arise from the peroneal artery = branch of posterior tibial

Question 47

what are the spinal cord levels of the lat comp

Answer 47

L5, S1-S2