Lecture 11 - Biomechanics of the Ankle and Foot (part 2) Flashcards
What are the 4 muscles of the anterior compartment of the ankle and foot?
- anterior tibialis
- extensor hallucis longus
- extensor digitorum longus
- peroneus tertius
Which muscle of the anterior compartment is the largest dorsiflexor and also acts as an inverter?
anterior tibialis
What are the 2 effects of weakness of the anterior tibialis?
impairs control of dorsiflexion during gait: foot slap or foot drop
What is the effect of tightness in the anterior tibialis?
can contribute to cavus foot
What are the 3 muscles of the posterior compartment of the foot?
- gastrocnemius
- soleus
- plantaris
What 2 muscles form the tricep surae?
gastrocnemius and soleus
Where does the gastrocnemius and soleus attach at?
achilles tendon
Which tendon is the thickest and strongest of the body?
achilles tendon
What kind of movement does the achilles tendon provide?
plantarflexion
What kind of moment arm for inversion does the achilles tendon have?
small moment arm
What does the achilles tendon do during running?
it stores energy
What kind of muscle is the gastrocnemius?
multi-joint muscle
Where does the gastrocnemius cross?
knee and ankle
What is the effect of weakness in the gastrocnemius?
decreased plantarflexion strength
What is the effect of tightness in the gastrocnemius?
limits dorsiflexion ROM
When is the clinical test to identify weak knee flexors positive?
when there is active contraction of the gastrocnemius
What kind of muscle is the soleus?
single-joint muscle
Is the soleus affected by knee position?
no
Which muscle can contribute to knee stability in the presence of quadricep weakness?
soleus
What is the effect of weakness of the soleus?
loss of plantarflexion strength
What is the effect of tightness in the soleus?
restrict forward progression of the tibia
What can a tight soleus contribute to?
genu recurvatum
What are the 2 muscles of the lateral compartment of the foot?
- peroneus longus
- peroneus brevis
What 2 muscles are the primary evertors?
peroneus longus and brevis
Which muscle is twice the size of peroneus brevis?
peroneus longus
What is the effect of weakness and tightness in the peroneus longus+brevis muscles?
supinated foot during standing
____ strength > ___ strength
plantarflexion, dorsiflexion
Which 3 factors affect foot muscle strength?
sex, age, joint position