Biomechanics of leg/lower limb muscles

Question 1

How are the gastroc and soleus different in terms of movement capabilities?

Answer 1

The gastroc crosses the knee joint in addition to the ankle, making it aid in knee flexion in addition to ankle plantar flexion

Question 2

What movement capabilities does the extensor digitorum longus have?

Answer 2

Strong ankle dorsiflexor due to lever arm being perpendicular to the ankle axis. Mild pronatory force across the subtalar axis and longitudinal midtarsal axis

Question 3

What is the difference between extensor digitorum longus and peroneus tertius in terms of movement capabilities?

Answer 3

Basically the same movements, although peroneus tertius has a longer lever arm for pronation about the subtalar axis and longitudinal midtarsal axis

Question 4

What are the possible movements for the extensor hallucis longus muscle?

Answer 4

Strong neutral dorsiflexor of the ankle, hallux dorsiflexor, weak inverter of the STJ

Question 5

Where does the tibialis anterior originate and insert? What movements can it perform?

Answer 5

Originates on the medial border of the tibia, inserts on the base of the first metatarsal/medial cuneiform. Due to being medial to the STJ axis and nearly perpendicular to the ankle axis, it inverts the STJ and dorsiflexes the ankle.

Question 6

What is the motion of the peroneus longus muscle?

Answer 6

Plantar flexes the ankle and everts the STJ

Question 7

Where does the peroneus longus muscle originate and insert?

Answer 7

Originates on the lateral aspect of the fibula, wraps posteriorly and inferiorly to the lateral malleolus, and inserts onto base of the first MT and the medial cuneiform

Question 8

What is the motion of the peroneus brevis muscle?

Answer 8

Everts the foot and plantar flexes the ankle, stronger everter of the STJ than peroneus longus