L9.2 Ankle and Foot joint

Question 1

Talocrural joint

Answer 1

• Talocrural - ankle joint(Hinge)
• Mortise = MED + LAT malleoli sockets + INF transverse lig
• ANT trochlear wider → dorsiflex → better contact b/w talus & mortise = ↑stability
• Capsule → encloses joint cap to neck of ANT talus

Question 2

Collateral ligaments

Answer 2

• Collateral: triangular, blends with joint capsule:
  
  • MED (Deltoid): MED malleolus → distal ends (triangular shaped)
    
    • (SUP): Tibionavicular, tibiocalcaneal, POS tibiotalar
    • (DEEP): ANT tibiotalar
    • Limits overeversion
  • LAT: 3 separate parts; Prox LAT malleolus → distal ends
    
    • Provides movement
    • ANT talofibular (most commonly sprained), Calcaneofibular (LAT), POS talofibular
  • (movements not limited to sagittal plane)
  • During DF → slight coronal plane action (ADD) of talus
  • During PF → slight coronal plane action (AB) of talus

Question 3

Stability of the talocrural joint

Answer 3

• LoG ANT of ankle joint
• Need to recruit fatigueable muscles (gastroc & Soleus) to provide stability
• Good stability, except LAT (due to 3 discrete parts of LCL)
  
  • ∴ mainly ANT talofibular lig sprains from inversion

Question 4

Blood & Nerve supply of the talocrural joint

Answer 4

• Blood supply: Malleolar branches of fib & ANT/POS tibial branches
• Nerve supply: Tibial & deep fib N

Question 5

Subtalar (talocalcaneal) & talocalcaneonavicular joint

Answer 5

• talocalcaneonavicular joint (functionally part of the subtalar joint)
• Both modified B&S joints
• Substentaculum cali: horizontal eminence → b/w articular surfaces of calcenous
  
  • Spring, talocrural, MED talocalcaneal lig attaches
• Functions tgt → Inversion & eversion

Question 6

Calcaneocuboid joint

Answer 6

• Plane synovial → slight gliding (slight pronation & supination)
• Pronation = Eversion (Subtalar & TCN) + LAT rotation (at calcaneocuboid)
  
  • *Flat feet → hyperpronated feet
• Supination = Inversion (Subtalar & TCN) + MED rotation (at calcaneocuboid)
  
  • *High arch feet → hypersupinated feet

Question 7

Midtarsal joint

Answer 7

• Calcaneocuboid + talocalcaneonavicular joint
• JUST an anatomical relationship

Question 8

Main ligaments of the feet

Answer 8

• Spring (Plantar calcaneonavicular)
  
  • Support for talus INF
  • Maintain MED longitudinal arch
• Interosseous talocalcaneal
  
  • In sinus tarsi
  • Allows Inv & Ev → limits hyper inv/ev
• Cervical lig of talus
  
  • LAT continuation of interosseous talocalcaneal lig
  • Limits INV
• Plantar lig: maintains long arch of foot
  
  • Long: calcaneous → distal cuboid & MT bases
    
    • Forms retinaculum for fibularis longus
  • Short: calcaneous → prox cuboid (deep)

Question 9

Other ligaments of the feet

Answer 9

• Bifurcate lig
  
  • Dorsolat foor
  • 2 parts → support TCN & calcaneocuboid joint
• Plantar aponeurosis
  
  • Binds skin of foot → allows/provides grip
  • Maintains long arches of foot
  • Clin sig:
    
    • Plantar fascitis → Pain in deep tendon → transfers to apo → DF of hallux = pain
    • Bone spurs in calcaneous

Question 10

Toe joints & their ligaments

Answer 10

• MTP joint: Condylar
• IPJ: hinge with some rotation
• MT:
  
  • Heads connected deep transverse MT lig
  • Links volar plates of MP joints
    
    • In joint capsule at MTP & IP
    • ↑articular surface
    • Limits hyperextension
  • Collateral lig
    
    • Stabilises F/E
    • Taut in E at IP, lax at MTP
    • Allows AB/ADD

Question 11

Foot arches

Answer 11

• Important for transferring weight from heel to LAT margins of foot → ball → big toe
• Stability base while standing
• b/w 3 weight bearing points:
  
  • Longitudinal (2):
    
    • MED: calcaneous + navicular + MED 2 cuneiforms
      
      • Supported by: Plantar apo; spring lig; TA, TP; FHL
    • LAT: Calcaneous + cuboid + LAT cuneiform
      
      • Supported by: Plantar apo; long&short plantar lig; Fibularis longus
  • Transverse (1): (hemi-arch of each foot)
    
    • Cuboid + 3 cuneiform
      
      • Supported by: fibularis longus; tibialis ANT ‘sling’; Tibialis POS

Question 12

Foot stability

Answer 12

• Foot stability:
  
  • Poor bony stability
  • Ligamentous support required for STATIC activity
  • Muscular support require for DYNAMIC activity