lower limb (foot ankle and tib/fib) Flashcards
the lower leg
Space between popliteal fossa (knee) and tarsaltunnel in the ankle/foot (most major structures passthrough these)
- tibia/fibula bones and muscles divided into three compartments:
Anterior
Lateral
Posterior
tibia
Larger and stronger than fibula
- Weight-bearing
- Triangular in cross-section, apex anterior
- Numerous muscle attachments
- Tibial condyles/plateau proximally
- Distal tibia flattened (plafond) to articulate with talus
- medial tubercle (malleolus
fibula
- Thinner and weaker than tibia
- Non-weight-bearing
- Important muscle attachment site, completely enclosed
- Enlarged distal end (malleolus) longer than tibial malleolus
tibia/fibula articulations
Form a bony ring
- Proximal tibio-fibular joint (synovial)
- Inter-osseous membrane:
- fibrous connective tissue
- Increases area for muscle attachment
- Openings for nv vessels
- Distal tibio-fibula joint
-Fibrous joint (syndesmosis)
-Thickening of membrane with anterior/posterior tibio-fibular ligaments
- Integral to strength of ankle
muscle compartments
Posterior:
- Deep/superficial
- Action:
- Plantar-flex foot
- Flex toes
- Invert (medially rotate) foot
- Achilles tendon
- Lateral:
- Peroneus longus/brevis
- Evert (externally rotate) foot - Anterior compartment:
- Four muscles
- Action:
- Dorsi-flex foot
- Extend toes
- Invert foot
foot
Equivalent to hand/wrist
Divided into:
- Phalanges (14)
- Metatarsals (5)
- Tarsals (7)
Can also be divided as:
- Forefoot
- Midfoot
- Hindfoot
Dorsal / plantar surfaces
Numerous and variable accessory
phalanges/toes
Hallux and 2nd-5th toes
- 2 in hallux (great toe)
- 3 in other digits (proximal, middle, distal)
- Each has BASE, shaft, head
- Separated by interphalangeal joints
metatarsals
Numbered 1-5
1st is shortest and strongest
2nd longest
Base, shaft, head/neck
Articulates distally at metatarso-phalangeal joints
Proximally at tarso-metatarsal (lisfranc) jointswith adjacent metatarsals and tarsals
Sesamoid bones
mid foot/ distal tarsals
Navicular (boat)
- Cuneiforms (wedge)
- Medial
- Intermediate
- Lateral
- Cuboid (cube)
hindfoot
- Separated from mid foot (navicular/cuboid) bychopart joints
- TaLUS (ankle) articulates with tibia/fibula
- Calcaneum (HEEL)
- Best visualised with ankle projections
calcaneum
- short bone forms major weight-bearing portionof foot
- Commonly fractured in falls from height
- Multiple tuberosities / articular surfaces:
- Calcaneal tuberosity and process
- Anterior/posterior articular surface (sub-talarjoint)
- Sustentaculum tali (horizontal shelf of bone)
- Anterior process
- Peroneal (fibular) tubercle
talus
Formed of three parts:
- head (distal)
- Neck
- Body
- body articulates with tibia/fibula, almost entirelycovered by hyaline cartilage (talar dome)
- Inferior articular facets correspond with calcaneumfacets to form sub-talar joint
- Narrowing of neck forms tarsal sinus with calcaneaal sulcus
talus (IF)
Interesting features:
- Majority covered in hyaline cartilage (60%)
- No muscular/tendinous attachments
- Prone to avascular necrosis in fractures due toarterial supply through neck
- Fractures known as aviator’s
ossification centred phalanges (fore/midfoot)
Primary: diaphysis/shaft (9-15th week in utero)
Secondary: proximal epiphysis/base only (2-8years)
Fuse by 18 years
OC metatarsals (fore/midfoot)
Primary: diaphysis/shaft (9-10th week in utero)
Secondary:
Base/proximal epiphysis hallux (3 years)
Heads/distal epiphysis 2-5th metatarsals (3-4years)
Base 5th metatarsal apophysis
fuse 17-20 years
