Territories of Nerve Endings of the Medial Plantar Nerve within the Abductor Hallucis Muscle: Clinical Implications for Potential Pain Management.

This study aimed to elucidate the intramuscular distribution pattern of the medial plantar nerve and determine its motor nerve ending territories within the abductor hallucis muscle using modified Sihler's staining and external anatomical landmarks. The study included 40 specimens of the abductor hallucis muscle (13 men and seven women) from formalin-fixed (ten cadavers) and fresh cadavers (ten cadavers), with a mean age of 77.6 years. The entry point of the medial plantar nerve into the muscle was examined, followed by Sihler's staining to analyze the intramuscular distribution pattern and motor nerve ending location within the abductor hallucis muscle. Ultrasound- and palpation-guided injections were performed to verify the applicability of motor nerve ending location-based injections. The areas with the highest concentrations of nerve entry points and nerve endings were identified in the central portion of the muscle. Ultrasound- and palpation-guided injections were safely positioned near the densest nerve ending region of the muscle. These detailed anatomical data and injection methods would be beneficial for proceeding with safe and effective injection treatments using various analgesic agents to alleviate abductor hallucis muscle-associated pain disorders.