In the patellar tendon reflex, the quadriceps muscle group is stretched, and the reflex response causes the quadriceps muscle group to contract while the antagonist muscle group, the hamstrings muscle group, relaxes. This combination of muscle contraction and relaxation causes the leg or knee to extend. In the Achilles tendon reflex, the gastrocnemius muscle is stretched and the reflex response causes the gastrocnemius muscle to contract while the antagonist muscle, the tibialis anterior muscle, relaxes. This combination of muscle contraction and relaxation causes the foot or ankle to plantarflex.
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Identify the muscle group that is being stretched in the reflex. In the patellar tendon reflex, the quadriceps muscle group is stretched. Show more…
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Sri K.
In the patellar tendon reflex arc, the patellar ligament is stretched, which stretches the quadriceps femoris muscle of the thigh. This reflex will cause the quadriceps femoris to contract and the hamstrings to relax.
Plantar flexion The only muscle of the lower leg that flexes the knee and plantar flexes the foot is the soleus muscle. Flexor hallucis longus Flexor digitorum longus Both the gastrocnemius muscle and the soleus muscle insert on the calcaneus via the calcaneal tendon. Using the great toe to push off for walking is achieved by contracting the flexor hallucis longus muscle. Dorsiflexion Gastrocnemius The muscles of the posterior compartment of the leg all contribute to the flexion of the foot.
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