Is the Radiographic Appearance of the Hallucal Tarsometatarsal Joint Representative of Its True Anatomical Structure?

Abstract

The medial cuneiforms and first metatarsals were identified in 515 randomly selected specimens at the Hamman-Todd osteology collection in the Cleveland Museum of Natural History in Cleveland, Ohio, and the transverse plane angulation of the hallucal tarsometatarsal joint was determined by direct measurement of the selected bones. Medial cuneiforms were subsequently separated into three categories corresponding to the amount of measured obliquity. The first tarsometatarsal joint was reassembled, and the paired medial cuneiforms and first metatarsals were radiographed at different declination angles in inverted, everted, and rectus positions. Radiographic evaluation revealed discordance between the appearance of atavism and true atavism in the cuneiform. Specifically, it was determined that the position of the hallucal tarsometatarsal joint significantly influenced the appearance of atavism in the cuneiform. It is concluded that the position of the first ray in an anteroposterior radiograph can produce the appearance of an increased obliquity angle of the medial cuneiform, resulting in an inaccurate representation of the hallucal tarsometatarsal joint. (J Am Podiatr Med Assoc 92(9): 491-498, 2002)