Plantar Fasciosis can be a very difficult condition to treat because of the intricate anatomy of the foot and ankle complex. To complicate issues, we now know that many lower quarter problems root from lumbopelvic and hip dysfunction as well. In previous posts, TSPT has done a literature review of the condition as well as talked about new treatment methods regarding plantar fasciosis. In these posts, one aspect of management we did not discuss in depth is assessing for neuropathic pain. From my clinical experiences and the experiences of my colleagues at the Harris Health System, many patients with plantar fasciosis have positive neural provocation tests for the distal branches of the tibial nerve.
After the tibial nerve passes around the medial malleolus, it splits into three distal branches: the medial plantar nerve, lateral plantar nerve, and medial calcaneal branch. Specifically, the lateral plantar nerve innervates the fifth and lateral 1/2 of the fourth toes and provides motor input to many of the intrinsic foot muscles. The nerve passes laterally across the foot and splits between the flexor digitorum brevis and quadratus plantae.
To assess for tibial nerve adverse neural tension, have the patient lie supine. Passively extend the toes, dorsiflex and evert the ankle. This combined movement place a stress across the tibial nerve and its distal branches. Ask the patient if this position changes their primary symptoms (better, worse, or the same). Next, passively perform a straight leg raise maintaining the foot and ankle components. If this position recreates their primary symptoms, they have positive neural tension in the tibial nerve* (remember to test bilaterally as well). To further assess the tibial nerve, adduct and internally rotate the lower extremity. If the test is positive, appropriate treatment options include nerve sliders, tensioners, and manual therapy.
*When performing a straight leg raise, you are changing the hip component. No musculoskeletal structure courses from the hip to the ankle, so if symptoms change it must be the nervous system that is being assessed.
-Lateral plantar nerve pain can be a contributing factor to plantar fasciosis pain.
-By performing the proper assessment (discussed above), you can identify if neural tension is part of your patient's symptoms.
-Do not underestimate the impact of the peripheral nervous system in musculoskeletal dysfunction.