MSK5 L18 - Leg and Ankle Flashcards
What roles do the foot and ankle have in stability?
2
- stable base to support body weight during stance and locomotion
- rigid lever for effective push-off during gait
What roles do the foot and ankle have in mobility?
3
- influences other joints
- flexible for shock absorption
- conform to changing surfaces
What is the name of the joint where the tibia and fibula articulate proximally? What kind of joint is this?
superior tibiofibular joint
synovial joint
What is the name of the joint where the tibia and fibula articulate distally? What kind of joint is this?
inferior tibiofibular joint
syndesmosis - fibrous joint with limited movement
What is the layer between the tibia and fiula called?
Interosseous membrane
What ligaments strengthen the inferior tibiofibular joint?
2
- anterior tibiofibular ligament
- posterior tibiofibular ligament
What are the names of the 7 tarsals?
- talus
- calcaneus
- cuboid
- navicular
- cuneiform medial
- cuneiform intermediate
- cuneiform lateral
What are the three arches of the foot?
- medial longitudinal
- lateral longitudinal
- transverse
What purposes do the arches of the foot have?
3
- stability and flexibility
- absorb and distribute force
- aid propulsion
What kind of joint is the ankle?
hinge joint
What movements can the ankle perform?
plantarflexion/dorsiflexion
What bones form the ankle socket?
- medial malleolus (tibia)
- lateral malleolus (fibula)
- inferior surface of the distal end of tibia
What tarsal do the tibia and fibula both articulate with?
talus
What is the name of the joint between the talus and calcaneus?
subtalar joint
What movements happen at the subtalar joint?
inversion and eversion
What movements happen at the subtalar joint?
inversion and eversion
What movements happen at the subtalar joint?
inversion and eversion
What function do the lateral collateral ligaments have?
restrict inversion
What function do the medial collateral (deltoid) ligaments have?
restricts eversion
Which of the collateral ligaments is strongest?
medial collateral (deltoid) ligament, lateral is commonly damaged in ankle sprain
What are the leg muscle compartments?
- anterior (lateral ish)
- lateral (lateral)
- deep (middle of leg)
- posterior (and medial ish)
- superficial (soleus ish)
What muscle causes plantarflexion?
gastrocnemius
Where does the gastrocnemius originate?
Where does it insert?
- originates at the medial and lateral femoral condyles
- inserts at the calcaneus via the calcaneal (Achilles) tendon
What are the functions of the gastrocnemius at the knee and ankle? What role does it have in gait?
- flexion at the knee
- plantarflexion at the ankle
- propulsion in gait
What nerve innervates the gastrocnemius?
tibial
T or F?
The soleus crosses the knee joint
False, the soleus is deep to the gastrocnemius and doesn’t cross the knee
Where does the soleus originate?
3
- tibia and fibula
- interosseous membrane
Where does the soleus insert?
calcaneus via the calcaneal tendon
What are the functions of the soleus at the knee and ankle? What is it important for?
- no function at the knee
- plantarflexion at the ankle
- important for posture during standing and for propulsion during gait
What nerve innervates the soleus?
tibial
What are tendons held in place by?
retinaculum (fibrous tissue)
What do tendons have associated with them to reduce friction?
bursae
What 3 muscles compose the posterior compartment of the leg?
- tibialis posterior
- flexor digitorum longus (FDL)
- flexor hallicus longus (FHL)
Where do the tendons of the muscles of the posterior muscle compartment of the leg pass over?
the medial malleolus
What action do the deep flexors perform at the ankle?
plantarflexion, all muscles
What action do the deep flexors cause at the toes?
What muscles cause the movement?
- flexion of the big toe by FHL
- flexion of other toes by FDL
What group of muscles stabilise the medial longitudinal arch?
deep flexors (FDL, FHL, TP) and anterior leg muscles (TA, EDL, EHL)
What ligament supports the head of the talus? What helps to increase support to maintain the medial arch?
spring ligament, tibialis posterior tendon
What causes flat foot deformity?
if the srping ligament ruptures, it cannot support the head of the talus anymore. could be due to ruptured TP tendon as a result of aging, trauma or denervation
What three muscles compose the anterior muscle compartment?
- tibialis anterior (TA)
- extensor digitorum longus (EDL)
- extensor hallicus longus (EHL)
Where does the tibialis anterior insert?
medial cuneiform, base of 1st metatarsal
Where does the EDL insert?
distal phalanges of toes 2-5
Where does the EHL insert?
distal phalanx big toe
Where do the anterior muscle compartments tendons pass under?
extensor retinacula
What movement does the anterior muscle compartment cause at the ankle?
dorsiflexion - all muscles
What movement does the anterior muscle compartment cause at the toes?
extension of the hallux (EHL) and toes (EDL)
What joint uses the tibialis anterior to cause inversion?
subtalar
What two muscles compose the lateral compartment?
- fibularis (peroneus) longus
- fibularis (peroneus) brevis
Where do the lateral compartment muscles originate?
fibula
Where does the fibularis (peroneus) longus insert?
base of the 1st metatarsal (passes under foot)
Where does the fibularis (peroneus) brevis insert?
base of the 5th metatarsal
What arch do the lateral compartment muscles help stabilise?
transverse
What movement do the lateral compartment muscles cause at the ankle?
weak plantarflexion (both muscles)
What movement do the lateral compartment muscles cause at the subtalar joint?
eversion (both muscles)
What arch do both the lateral compartment muscles stabilise?
longitudinal
What arch do both the lateral compartment muscles stabilise?
longitudinal
What arch does the fibularis longus stabilise?
transverse, due to it’s course along plantar surface of foot)
Why is arch support important?
for stability when weight bearing
What muscles tendons support the medial longitudinal arch? What aspect of the foot?
- TA
- TP
- long toe flexor tendons (when walking)
medial aspect
What muscles tendons support the lateral longitudinal arch? Which aspect of the foot?
- fibularis longus
- fibularis brevis
lateral aspect
What muscles tendos support the transverse arch? On which aspect of the foot?
- fibularis longus
- small intrinsic muscles of the foot