MRI with user outlined plantar intrinsic and extrinsic muscles group. A sagittal image of a foot representing the localization of serial axial MRI (a). A typical example of MRI with a manually painted three plantar intrinsic muscle groups (b). A sagittal image of a lower leg representing the localization of serial axial MR images (c). A typical example of the analyzed image for two plantar extrinsic muscles (d). White arrows show the site of the analyzed images. The painted area excludes the bones and the central band of the plantar fascia as well as tendons, fat, connective tissue, nerve tissue and blood vessels.