The Medial Longitudinal Arch Is Supported By The Intrinsic Plantar Musculature

• Published in: Journal of athletic training 2001-01, Vol.36 (2), p.S-65
• Main Authors: Fiolkowski, P, Bishop, M, Brunt, D S, Woo, R, Horodyski, M B
• Format: Article
• Language: English
• ISSN: 1062-6050

The medial longitudinal arch (MLA) had often been described as an important structure of the foot. Its role in shock absorption and its relation to movements have been previously analyzed. However, there seems to be some disagreement in the literature as to the role of foot structures in the maintenance of the medial longitudinal arch. This project was undertaken with the intent of elucidating the function of the intrinsic musculature of the plantar aspect of the foot in the maintenance of the MLA. Nine healthy adults, free lower extremity pathology, served as participants for this study. Navicular drop was used to measure the height of the MLA. The participants were seated and the foot placed in subtalar neutral, and the height of the navicular tubercle above the ground was measured. The subjects then stood, and the height of the navicular tubercle was measured again. EMG were collected at 1000 Hz from the abductor hallicus muscle. Maximal voluntary contraction (MVC) was maintained for 5 seconds while data were recorded. 1% lidocaine was then injected posterior and inferior to the medial malleolus, in order to achieve a tibial nerve block at the level of the ankle. Anesthetic effect was determined by a loss of tactile sensation using Semmes-Weinstein filaments. EMG data were again recorded from the abductor hallucis muscle, and the participants were again measured for navicular drop, using the same method as previously described. Data were compared between conditions using a paired t-test. The results indicate that there was a significant decrease in EMG. The integrated values following the nerve block were 28% of the control values for MVC. This corresponded to a significant increase (p