ABSTRACT
BACKGROUND: The metatarsal head and proximal phalanx exhibit considerable asymmetry in their shape and geometry, but there is little documentation in the literature regarding the prevalence of structural characteristics that occur in a given population. Although there is a considerable volume of in vivo and in vitro experiments demonstrating first metatarsal inversion around its longitudinal axis with dorsiflexion, little is known regarding the applicability of specific morphometrics to these motions. METHODS: Nine distinctive osseous characteristics in the metatarsal head and phalanx were selected based on their location, geometry, and perceived functional relationship to previous studies describing metatarsal motion as inversion with dorsiflexion. The prevalences of the chosen characteristics were determined in a cohort of 21 randomly selected skeletal specimens, 19 of which were provided by the anatomical preparation office at the University of California, San Diego, and two of which were in the possession of one of us (M.D.). RESULTS: The frequency of occurrence of each selected morphological characteristic in this sample and the relevant summary statistics confirm a strong association between the selected features and a conceptual two-axis kinematic model of the metatarsophalangeal joint. CONCLUSIONS: The selected morphometrics are consistent with inversion of the metatarsal around its longitudinal axis as it dorsiflexes.
Subject(s)
Metatarsal Bones/anatomy & histology , Metatarsophalangeal Joint/physiology , Range of Motion, Articular/physiology , Toe Phalanges/anatomy & histology , Biomechanical Phenomena , Humans , Metatarsal Bones/physiology , Toe Phalanges/physiologyABSTRACT
Onychomatricoma (OM) is a fibroepithelial tumor of nail matrix that occurs in the digits of both the hands and feet. This was first reported by Baran and Kint. They initially described 3 cases, all of which demonstrated a filamentous tumor of matrix tissue that resulted in a thickened funnel-shaped nail. Although apparently benign, it is subject to recurrence, and long-term follow-up is recommended because it is not known whether there is a conversion to malignancy. Even though this neoplasm was first described more than 18 years ago, there remains a dearth of case reports (currently fewer than 50) in the literature. This is a single case report and literature review. Levels of Evidence : Therapeutic, Level IV.
