MSK DSA 8-9

head of fibula articulates w/

lateral condyle of tibia [NOT femur]

3 structures connecting tibia and fibula

1. proximal [superior] tibiofibular joint

   1. small plane-type synovial joint

   2. allows slight gliding movements

   3. helps dissipate forces transmitted up from ankle

2. interosseous membrane

3. distal [inferior] tibiofibular joint

   1. syndesmosis [fibrous joint]

   2. provides strong stability for ankle joint

mortise

“socket”

formed by medial and lateral malleoli of tibia and fibula

grips talus securely

talus

• sits on calcaneus

• articulates w/ tibia/tubula

• transmits body weight

calcaneus

• largest, heel bone

• achilles tendon insertion

navicular

• boat-shaped

• medial side

• supports arch

medial cuneiform

• largest cuneiform

• articulates w/ 1st metatarsal

intermediate cuneiform

• smallest

• wedge-shaped

• stabilizes 2nd metatarsal

lateral cuneiform

• btwn cuboid & intermediate

• behind 3rd metatarsal

cuboid

• lateral

• cube-shaped

• groove for fibularis longus tendon

Tarsal bones [7]

• calcaneus

• talus

• navicular

• cuboid

• 3 cuneiform bones

• only talus articulates w/ tibia & fibula at ankle joint

• ossification takes place in all tarsal bones by 5th yr

metatarsals [5]

• bases promixal

  • base of 1st metatarsal = attachment of fibularis longus muscle

  • base of 5th metatarsal = palpable landmark at midpoint of lateral aspect of foot

    • attachment of fibularis brevis muscle

• heads distal

• sesamoid bones

lateral ligaments of ankle

stabilize ankle laterally; prevent excessive inversion

1. anterior talofibular ligament [ATFL]

2. calcaneofibular ligament [CFL]

3. posterior talofibular ligament [PTFL]

anterior talofibular ligament [ATFL]

• lateral malleolus → talus

• weakest, most commonly injured

calcaneofibular ligament [CFL]

• lateral malleolus → calcaneus

• resists inversion when foot is in neutral

posterior talofibular ligament [PTFL]

• lateral malleolus → posterior talus

• strongest

medial ligament of ankle

deltoid ligament

• stabilizes ankle medially; resists excessive eversion

• helps maintain medial longitudinal arch

• medial malleolus → talus, navicular, & calcaneus

• made of 4 separate ligaments

distal tibiofibular ligaments

[syndesmotic ligaments]

• bind tibia & fibula together at ankle mortise

• important in high ankle sprains

avulsion fracture of tuberosity of 5th metatarsal

when foot suddenly & violently inverted, tuberosity of 5th metatarsal may be avulsed by tendon of fibularis brevis

• associated w/ severely sprained ankle

• pain & edema at base of 5th metatarsal

plantar fasciitis

• repeated minor trauma → ossification in posterior attchmnt of aponeurosis

• calcaneal spur [heel spur] may form

subtalar joint

AKA talocalcaneal joint

• plane synovial joint

• allows inversion/eversion

talocalcaneonavicular joint

• ball-and-socket joint

• supported by spring ligament

transverse tarsal [midtarsal] joint

[Chopart’s joint]

• collective term for talonavicular part of talocalcaneonavicular joint

• imp for inversion/eversion of foot

tarsometatarsal joints

[lisfranc’s joint']

• plane synovial joints [gliding]

• strengthen transverse arch

• Lisfranc injury

  • occurs when bikers get foot caught in pedal clips or as result of high-E car accident

intermetatarsal joints

• gliding type synovial joints

metatarsophalangeal joints

• condyloid synovial joints

• permit flexion/extension & ab/adduction of toes

• lateral deviation of great toe at this joint

  • bunion

interphalangeal joints

• hinge synovial joints

• permit flexion/extension of toes

long plantar ligament

• calcaneus → cuboid

• helps maintain longitudinal arch of foot

short plantar ligament [plantar calcaneocuboid ligament]

• deep to long plantar ligament

• anterior surface of calcaneus → cuboid

plantar calcaneonavicular [spring] ligament

• calcaneus → navicular

• supports head of talus

• plays imp role in maintaining longitudinal arch of foot

bunion

localized swelling at medial side of 1st metatarsophalangeal joint [inflammatory bursa]

*unusually associated w/ hallux valgus

medial longitudinal arch

• highest & most important

• talar head is “keystone” of arch

lateral longitudinal arch keystone

cuboid

deep veins

located underneath deep fascia, course along arteries

superficial veins

located subcutaneously, eventually drain into deep veins through series of perforating veins [including great & small saphenous veins]

perforating vein

connects deep & superficial venous systems

plantar venous arch

formed by plantar digital veins [formed by venous plexuses within plantar regions of toes] & plantar metatarsal veins

dorsal venous arch

• formed by common digital veins [formed by dorsal digital veins & intercapitular veins] uniting w/ dorsal metatarsal

• drains into medial and lateral marginal veins

  • medial drains into great saphenous vein

  • lateral drains into small saphenous vein

• some veins from arch form anterior tibial vein [empties into popliteal vein]

popliteal vein

• formed by anterior tibial, posterior tibial, and fibular veins

• becomes femoral vein after piercing adductor magnus

• becomes external iliac vein after leaving thigh & running underneath inguinal ligament

femoral vein

• common site for deep vein thrombosis [DVT]

  • iliofemoral DVT carries greater risk of pulmonary embolism

• used to place central venous catheter or line

• used to deliver recreational drugs

internal iliac vein

• receives from inferior & superior gluteal veins

• drains into inferior vena cava

  • → drains into right atrium

long [great] saphenous vein

• longest vein in body

• superficial, continuation of medial marginal vein of foot

• passes anterior to medial malleolus

short [small] saphenous vein

• superficial, continuation of lateral margin vein of foot

• moves up posterior side of leg

virchow’s triad

contribute to venous thromboembolism [DVT formation]

1. increased tendency for intravascular clot formation [hypercoagulability]

2. increased structural changes in walls of affected vessels [changes in endothelial blood vessel lining]

3. decreased vascular blood flow [venous stasis]

DVT can be diagnosed by

1. venous decompression duplex ultrasound

2. doppler

3. CT

4. MRI

5. Serum D-dimer levels