week 12 - muscles of the foot ankle and knee Flashcards
3 flexors of ankle + foot
- tibialis posterior
- flexor digitorum longus
- flexor hallucis longus
nerve for flexors of ankle + foot
tibial nerve
tibialis posterior – origin
posterior shaft of tibia + fibula
tibialis posterior – insertion
- all 5 tarsal bones
- bases of metatarsals 2 - 4
tibialis posterior – action
- invert foot
- plantar flex ankle
flexor digitorum longus – origin
posterior surface of tibia
flexor digitorum longus – insertion
distal phalanges 2 - 5
flexor digitorum longus – action
- flex toes 2 - 5
- invert foot
flexor hallucis longus – origin
posterior fibula
flexor hallucis longus – insertion
distal phalanx of big toe
flexor hallucis longus – action
- flex big toe
- invert foot
3 arches in foot
- medial longitudinal (calcaneus to hallucis)
- lateral longitudinal (calcaneous to 5th metatarsal)
- transverse (base of the 1st and 5th metatarsals)
4 muscles of foot
- extensor digitorum brevis
- flexor digitorum brevis
- abductor hallucis
- abductor digiti minimi
general location of muscles of foot
- dorsal surface: extensor digitorum brevis (deep to extensor digitorum longus)
- plantar surface myo lie side-by-side:
> flexor digitorum brevis exends down center of foot from calcaneus to phalanges
> abductor hallucis is on big toe side of plantar surface
> abductor digiti minimi s on little toe side of plantar surface
nerves of muscles of foot
- tibial nerve (for myo on plantar surface)
- deep peroneal (for extensor digitorum brevis only)
extensor digitorum longus – origin
calcaneus (dorsal surface of)
extensor digitorum longus – insertion
toes 2 - 4 via extensor digitorum longus tendons
extensor digitorum longus – action
extend phalanges 2 - 4
extensor digitorum longus – nerve
deep peroneal nerve
flexor digitorum brevis – origin
calcaneus
flexor digitorum brevis – insertion
middle phalanges of toes 2 - 5
flexor digitorum brevis – action
flex middle phalanges of toes 2 - 5
flexor digitorum brevis – nerve
tibial nerve (burning sensation on bottom of foot –> plantar fasciitis)
plantar fasciitis + flexor digitorum brevis
- inflammation of the plantar fascia, the connective tissue on the sole of the foot
- often caused by overuse of the plantar fascia or arch tendon of the foot
- aka “policeman’s heel”
abductor hallucis – origin
calcaneus
abductor hallucis – insertion
proximal phalanx of big toe
abductor hallucis – action
abduct big toe
abductor hallucis – nerve
tibial nerve
abductor digiti minimi – origin
calcaneus
abductor digiti minimi – insertion
proximal phalanx of little toe
abductor digiti minimi – action
flex little toe (should be called the flexor digiti minimi)
abductor digiti minimi – nerve
tibial nerve
sesamoid bone of 1st metatarsal – location
- located along plantar surface of foot
- 1 to 2 sesamoid bones articulate w the metatarsal of big toe
- sesamoids are embedded within tendon of flexor hallucis brevis
sesamoid bone of 1st metatarsal – function
- helps big toe have more flexion, for stability + strength
- in general, sesamoids are found in locations where a tendon passes over a joint, such as the hand, knee, and foot; functionally, they act to protect the tendon and to increase its mechanical effect (patella is also a sesamoid bone)
extensor hallucis brevis – origin
calcaneus
extensor hallucis brevis – insertion
proximal phalanx of big toe
extensor hallucis brevis – action
extend big toe
extensor hallucis brevis – nerve
deep peroneal nerve
flexor hallucis brevis – location
plantar surface of foot
flexor hallucis brevis – origin
- cuboid
- lateral cuneiform
flexor hallucis brevis – insertion
proximal phalanx of big toe
flexor hallucis brevis – action
flex big toe
flexor hallucis brevis – nerve
tibial nerve
quadratus plantae – location
plantar surface of foot
quadratus plantae – origin
plantar surface of calcaneus
quadratus plantae – insertion
flexor digitorum longus tendon
quadratus plantae – action
flex toes 2 - 5
quadratus plantae – nerve
tibial nerve
lateral collateral ligament (LCL) – AKA
fibular collateral ligament
lateral collateral ligament (LCL) – location
- strong, thin strap that crosses knee joint
- runs from lateral epicondyle of femur to head of fibula
lateral collateral ligament (LCL) – function
- resists medial rotation of knee
- also stabilizes knee against genu varum stresses (often seen in bowlegged cowboys)
medial collateral ligament (MCL) – AKA
tibial collateral ligament
medial collateral ligament (MCL) – location
- broad ligament lies superficial to joint capsule of knee
- deep to pes anserinus tendon
medial collateral ligament (MCL) – function
- resists medial rotation of knee
- also protects against genu valgum (knock-knee) stresses
anterior cruciate ligament (ACL) – location
deep in the middle of the knee
anterior cruciate ligament (ACL) – function
- prevents tibia from moving anteriorly to femur
- also prevents medial rotation of the tibia, in relation to the femur
- athletes tear this when they hyperextend knee
posterior cruciate ligament (PCL) – location
deep in the middle of the knee (and works with ACL)
posterior cruciate ligament (PCL) – function
- prevents tibia from moving posteriorly under femur
- hyperflexion injuries tear PCL
- skiers tear these easily since they prevent rotary movement of knee
medial + lateral menisci of knee – location
- fibrocartilagnous discs attached to tibial condyles
- helps round femoral condyles sit comfortably on flat tibial plateaus
medial + lateral menisci of knee – function
- responsible for shock absorption
- increases surface area, distributes weight, and reduces friction
- moves sinovial fluid around in knee
deltoid ligament of ankle – location
- medial side of ankle
- made up of 4 ligaments forming a triangle (seriously strong ligament!)
- connects talus, calcaneus + medial malleolus
deltoid ligament of ankle – function
- allows 5 degrees of eversion
- sprains here are often in conjunction with avulson fracture
4 deltoid ligaments of ankle (names)
- posterior tibiotalar
- tibiocalcaneal
- anterior tibiotalar
- tibionavicular
lateral collateral ligaments of ankle – location
- lateral side of ankle
lateral collateral ligaments of ankle – function
- stabilize distal end of fibula to calcaneus + talus
- 3 ligaments that are most often torn during ankle sprains (bc nowhere near as strong as deltoid ligament on ankle’s medial side + most vulnerable when foot is inverted and plantar flexed)
3 lateral collateral ligaments of ankle (names)
- anterior talofibular ligament (ATFL) (most commonly torn)
- posterior talofibular ligament (PTFL)
- calcaneofibular ligament
extensor retinacula of ankle – location
crosses front of ankle
extensor retinacula of ankle – function
supports tendons of extensor muscles
posterior tibial artery
- pulse can be felt inferior + posterior to medial malleolus
dorsalis pedis artery
- pulse can be felt bw 1st + 2nd metatarsal bones along dorsal side of foot
- where the extensor hallucis endon is on dorsal foot