Simone Moroni, Marit Zwierzina, Vasco Starke, Bernhard Moriggl, Ferruccio Montesi, Marko Konschake
Surgical and Radiologic Anatomy October 2018
Copyright 2018 The Authors
JACO Editorial Reviewer: Nathan Hinkeldey, D.C., D.A.C.R.B.
The original article copyright belongs to the original publisher. This review is available from: https://ianmmedicine.org ©2019 Hinkeldey and the Academy of Chiropractic Orthopedists. This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Purpose: Neuropathy of the Baxter nerve (BN) seems to be the first cause of the heel pain syndrome (HPS) of neurological origin.
Methods: 41 alcohol–glycerol embalmed feet were dissected. We documented the pattern of the branches of the tibial nerve (TN) and describe all relevant osteofibrous structures. Measurements for the TN branches were related to the Dellon–McKinnon
malleolar-calcaneal line also called DM line (DML) for the proximal TT and the Heimkes Triangle for the distal TT. Additionally, we performed an ultrasound-guided injection procedure of the BN and provide an algorithm for clinical usage.
Results: The division of the TN was 16.4 mm proximal to the DML. The BN branches off 20 mm above the DML center or 30 mm distally to it. In most of the cases, the medial calcaneal branch (MCB) originated from the TN proximal to the bifurcation. Possible entrapment spots for the medial and lateral plantar nerve (MPN, LPN), the BN and the MCB are found within a circle of 5 mm radius with a probability of 80%, 83%, and 84%, respectively. In ten out of ten feet, the US-guided injection was precisely allocated around the BN.
Conclusions: Our detailed mapping of the TN branches and their osteofibrous tubes at the TT might be of importance for foot and ankle surgeons during minimally invasive procedures in HPS such as ultrasound-guided ankle and foot decompression
JACO Editorial Summary:
- The purpose of the article was to describe detailed anatomical variation in Tibial Nerve at the Tarsal Tunnel. Topographical accuracy of the Tibial Nerve within the Tarsal Tunnel was 73-94%.
- The tibial nerve and its branches have been implicated as causes in heel pain syndromes, specifically, neuropathy of Baxter’s nerve has a prevalence of 15-20%.
- Variation of branching was consistent with 32/40 specimens branching from the Lateral Peroneal Nerve, from the Tibial Nerve proximal to the bifurcation in 4/40 specimens, and within the bifurcation in 4/40 specimens.
- Accuracy of injection site of Baxter’s nerve was also tested. In 10/10 cases, researchers could inject Baxter’s Nerve.
- Implications of this research include improving diagnostic accuracy with Tinel’s sign. The sign elicits pain due to nervous sprouting from chronic compression and consequent axonal demyelination.
- Authors have demonstrated half of the asymptomatic, non-diabetic average population, older than 45 years, have abnormal electro diagnosis in the distal tarsal tunnel.
- Prevalence of atrophy of the abductor hallucis muscle is supposed to be an indirect diagnostic proof for Baxter’s neuropathy in MRI and this has been observed in 6% of the general asymptomatic population.
This article was written for the purpose of identifying anatomical variation of the Tibial Nerve within the Tarsal Tunnel which can have implications for surgeons who perform minimally invasive surgery for heel pain syndromes. For the manual therapist implications would include potential improvement in performing Tinel’s Sign. In addition, the paper adds differential diagnosis options to patients with heel pain syndromes.