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
OC tarsals (fore/midfoot)
Primary:
Calcaneum (3-4 month in utero) Talus (6 month in utero)
Cuboid (9th week in utero)
Lateral cuneiform (1 year)
Medial cuneiform (2 years)
Intermediate cuneiform (3 years)
ankle joint
Synovial saddle joint
Dorsi/plantar-flexion of thefoot
Other movements throughother joints
Referred to as the mortisejoint Formed by:
Tibial plafond superiorly
Lateral malleolus
Medial malleolus
Talar dome
Joint more stable with footin dorsi-flexion (important inposistioning)
OC (ankle/hindfoot) distal tibia
Primary: diaphysis/shaft (7th week in utero)
Secondary Distal epiphysis/medial malleolus (1year)
Fuses 15-17 years
OC secondary (ankle/hindfoot)
Secondary:
Calcaneum:
posterior surface (6-8 years).
Fuses at puberty
OC distal fibula (ankle/hindfoot)
Primary: diaphysis/shaft (8th week in utero)
Secondary Distal epiphysis/medial malleolus (1year)
Fuses 17-19 years
OC talus (ankle/hindfoot)
talus:
occasionally has posterior process
os trigonum if un-united by maturity
Normal variant
ankle joint description
Surrounded by synovial membrane and fibrous capsule
Ligamentous structures provide large amount of strength/stability Generally named by structures they connect
Tibio-fibular syndesmosis
Medial (deltoid)
fan-shaped
4 parts
Lateral
3 parts
Bony ring theory; injuries often a combination of bony/soft tissue abnormalities
Think about forces involved
tarsal joints
Remaining movements produced by smallerjoint in the midfoot:
inversion / eversion
Supination/pronation
Predominantly of:
Sub-talar
Talocalcaneonavicular
Calcaneocuboid
Synovial, supported by extensiveligamentous comple
other joints
Tarso-metatarsal (TMT)
Lisfranc joints / ligaments
Synovial plane joints
Sliding movement to allow pronation/supination
Greatest of 1st tmt joint
Metatarso-phalangeal (MTPJ)
Synovial ellipsoid
Flexion/extension
Some other movements
Supported by ligament complex
Interphalangeal joints
Hinge
Flexion/extension
arches of the foot
Help to distribute great forces on the foot
Longitudinal arch
Calcaneum to metatarsal heads
Most pronounced medially
Supported by plantar fascia/aponeurosis
Transverse arch
Supported by soft tissue anatomy Foot problems intrinsically linked to biomechanics ofthe anatomy; wide range of cause
musculature
Extensive and complex (especially plantarsurface), major components include:
Intrinsic (arise in foot)
Extrinsic (arise in leg)
Extensors (dorsal)
Flexors (Plantar
neurovascular supply
Supplied either:
Dorsally alongside extensor tendons
Anterior tibial/dorsalis pedis artery
Fibular nerves
great saphenous vein
Through tarsal tunnel medially
Posterior to medial malleolus
Posterior tibial artery (can palpate pulse)
Tibial nerve
Small saphenous vei
