LEG, ANKLE, FOOT

Question 1

Fibula:

Answer 1

Muscle attachment Ligament attachment Talocrural joint

Question 2

Tibia

Answer 2

• Largest distally & proximally Force transfer through tibia
• Anterior tibia under tension
• Posterior under compression - Tibial stress fractures
  90% posteromedial
  Anterior cortex:
  tension stress #’s
  poor blood supply
• External tibial torsion 20-40˚
• anterior convexity - repeatedly under tension due to posterior muscle bulk

Question 3

foot

Answer 3

7 tarsals, 5 metatarsals = improve MA for FHB

+2 sesamoid bones in tendons of FHB under 1st MTP

Question 4

weight transfer of foot

Answer 4

posterolateral > 1st and 2nd MTP when walking

Question 5

Motion segments of the foot

Answer 5

1st ray = 1st MT + medial cuneiform
2nd ray = 2nd MT + intermediate cuneiform
3rd ray = 3rd MT & lateral cuneiform
4th ray = 4th MT
5th ray = 5th MT

Question 6

Navicular stress fractures

Answer 6

Central zone of hypovascularity
Medial & lateral compressive forces through 1st & 2nd ray
> Maximum tensile load central 1/3

Question 7

arches of the foot

Answer 7

medial longitudinal arch
lateral longitudinal arch
transverse arch
Heads of MT should be weight bearing

Question 8

Heal

Answer 8

• Thin cortical shell around sparse trabecular bone
• Hydrodynamic shock absorber (filled with blood)
• Calcaneal fat pad returns 70% energy

Question 9

support of the arches

Answer 9

Passive structures (ligaments)
- plantar aponeurosis
- plantar calcaneonavicular (spring)
- short plantar lig
- tib ant and post tendons
- fib longus tendons
Active structures (muscles) Extrinsic:
• tibialis anterior
• tibialis posterior
• fibularis longus 
Intrinsic:
• Abductor hallucis
* Talus forced down when walking

Question 10

Plantar fascia

Answer 10

Deepest portion = plantar aponeurosis
2x tensile strength of other plantar ligaments
• Rich in proprioceptors (movement feedback)
Major support for the arches of the foot
• from medial calcaneal tuberosity
• Inserts onto capsules of all MTP joints

Question 11

Plantar fascia - rigid foot

Answer 11

Require a rigid foot for push-off during gait: PF pushes the calcaneal tuberosity posteriorly
+ MTP hyperextension
tensions the plantar aponeurosis
> holds foot rigid for push-off

Question 12

pronation

Answer 12

DF + eversion + Abduction

subtalor joints

Question 13

Supination

Answer 13

PF + inversion + Adduction

Question 14

Distal Tibiofibular Joint

Answer 14

The integrity of the distal tibiofibular joint is crucial for the stability of the talocrural joint
Distal tibiofibular joint:
Anterior tibiofibular ligament Posterior tibiofibular ligament Interosseous membrane

Question 15

PF

Answer 15

lose packed position

Question 16

The dome of the talus is widest anteriorly

Answer 16

i.e. the widest part of the talus is located in the mortise in DF ER of foot, relative to leg, turns the talus within the mortise
> forcing separation of the distal fibula & tibia
> tears anterior tibiofibular ligament +/- fractures fibula

Question 17

Joints of the foot

Answer 17

Subtalar joint = talocalcaneal
3 articulations
posterior articulations in articular capsule
anterior and middle enclosed in another capsule

Question 18

subtalor joint

Answer 18

3 articular facets between talus & calcaneus supination & pronation movements

Question 19

foot pronation

Answer 19

tibial IR

and vise versa

Question 20

Transverse tarsal

Answer 20

= TALONAVICULAR + CALCANEOCUBOID = joint between rearfoot & midfoot
• Intertarsal • TMT
• MTP
• PIP
• DIP