L7.3 Legs

Question 1

Tibia

Answer 1

• Most weight bearing
• Tibial epicondyles
• Tibial plateau (flat top bit)
• Intercondylar eminence (ACL &PCL starts here)
• Sharp ANT border & LAT border
• Rounded MED border
• Distally: MED malleolus → form socket of ankle joint
• Notch for fibula
• Soleal line: Point of origin for soleus
• Groove for TP tendon

Question 2

Fibula

Answer 2

• Fragile
• Prox: Head of fibula
• Distal: Lat malleolus
• Deep groove at distal end for tendons of everters

Question 3

Patella

Answer 3

• Upside down triangular shaped
• Sesamoid bone (bone within tendon/muscles)
• ANT: Prox end = base, distal end = apex
• POS: Lat facet → curvature → stops patellar from LAT dislocation (from Quad muscle pull)

Question 4

Injuries of the leg

Answer 4

• Tibial fracture (distal 1/3): also fractures fibula (fractures communicated) → endangers common fibular N
• Boot top fracture: when skiing
• March fracture: Shin splints (distal 1/3 → weight bearing and bad blood supply)

Question 5

Deep Fascia (crural fascia)

Answer 5

• Thick, continuous with:
• Fascia lata superiorly
• Periosteum of tibia ANT
• intermuscular Septa (deep)
• Ankle retinaculae INF → creates tarsal tunnel (ANT/POS)

Question 6

ANT leg muscles

Answer 6

• Tibialis ANT (dorsi/in): Lat condyle, IM → base of 1st MT
• Extensor hallucis longus: Fibula, IM → 1st EE
• Extensor digitorum longus: Lat condyle, fibula, IM → 4 tendons → EE of lat 4 phalanx
  
  • Under tarsal tunnel
• Fibularis tertius (dorsi/ev): Fibula, IM → Sup/dorsal of 5th MT

Question 7

ANT leg muscle injury

Answer 7

Tenoperiostitis: shin splints, muscle cause pain on tibia

Question 8

LAT leg muscles

Answer 8

• Origin: Fibula
• Fibularis longus (ev): sup fib → along groove of fibula → along plantar surface from deep, lat 5th MT → 1st MT
  
  • Helps maintain transverse arch
• Fibularis brevis: Inf fib → Plantar surface of 5th MT

Question 9

LAT leg muscle injury

Answer 9

May compress the common fibular N against head of fibula → foot drop

Question 10

Popliteal fossa

Answer 10

• SUP: Hamstring tendons
• INF: Gastrocnemius (Lat & Med heads)
• Deep: Popliteus muscle
• Contents:
  
  • Sciatic N → dividing into fib & tib branches → each sends out a cutaneous branch → sural N
  • Small saphenous veins
  • Politeal A & V + branches
  • Popliteal lymph nodes

Question 11

Clinical significance of the POS leg

Answer 11

• POS legs: Important for venous return (have tight fascia bound)
• Clinical significance:
  
  • Tenperiostitis (shin splints)
  • POS compartment syndrome
  • Deep vein thrombosis:
    
    • Veins lose elasticity (or prolonged inactivity → pooling of blood → and if legs injured → blood coagulate → thrombosis.

Question 12

Superior POS leg muscles

Answer 12

• SUP leg muscles: Inserts into calceneus:
• Gastrocnemius (2 heads): distal head of femur → archilles tendon → calceneus
  
  • Vertically oriented, FAST twitch (white fibres) → postural muscle, initiation/sprinting
• Soleus: Tibial Soleal line, Fibula, IM → joins archilles tendon
  
  • Obliquely oriented fibres, SLOW twitch (red fibres) → works during long walks
  • Thick belly, has soleus sinus
• Plantaris: Lat supracondylar ridge → archilles tendon

Question 13

Clinical significance of the SUP POS leg muscles

Answer 13

• Clinical significance:
• Calf strain, Venous return problems
• Archilles tendinitis

Question 14

DEEP POS leg muscles

Answer 14

• Popliteus: Lat condyle of femur → MED ANT of popliteal fossa
  
  • Oblique fibres → unlocks knee joint
  • Intracapsular pathway
• Tibialis POS: Tibia, Fib, IM → Medial heel (navicular, medial cuneiform)
  
  • Inversion, maintains longitudinal arch of foor
• Flexor digitorum longus: POS tibia → lat phalanges
• Flexor hallucis longus: Fibula → distal phalanx of hallux