Patients with lower back pain due to L5 and S1 nerve root irritation often complain of calf cramps, especially at night. The strong calf muscles are responsible for you to be able to walk on your toes. These muscles are especially important in the push-off phase of walking on level surfaces as well as on inclines and steps.
To be able to test the strength of the calf muscles, the best way is to have the patient stand on one leg. The patient then lifts the heel off the floor. Normally, there is at least a span of 5″ between the surface of the floor and the undersurface of the heel.
When the patient is examined to walk on their toes, one has to assess not just the ability to perform this type of walking but the ability of the patient to raise the heel of the floor by about 4-5″.
Similarly, when the patient is instructed to walk on heels, there should at least be a span of 3-3.5 inches between the floor and the undersurface of the big toe joint known as the first metatarso-phalangeal joint.
The muscles that perform plantar flexion of the foot are:
- medial gastrocnemius (L5, S1 through the tibial nerve)
- lateral gastrocnemius (L5, S1 through the tibial nerve)
- soleus (L5, S1 through the tibial nerve)
- tibialis posterior (L5, S1 through the posterior tibial nerve)
- flexor digitorum longus (L5, S1 through the posterior tibial nerve)
- flexor hallucis longus (L5, S1 through the posterior tibial nerve)
- peroneus longus (L5, S1 through the superficial peroneal nerve)
- peroneus brevis (L5, S1 through the superficial peroneal nerve)