Accessory navicular: A heritable accessory bone of the human foot

Abstract

The accessory navicular is a supernumerary bone of the human foot located medial to the navicular tuberosity and represents a secondary center of ossification that has failed to fuse to the main body of the navicular. Three forms of the accessory bone have been identified: Type I is an independent ossicle that is often embedded within the tibialis posterior tendon; Type II is a triangular accessory bone that attaches to the navicular tuberosity by means of a cartilaginous or fibrocartilaginous bridge; and Type III represents a fused Type II, which forms a hook-like protuberance extending from the tuberosity. The Type II accessory navicular is the most common of the three forms and is the most readily identifiable in skeletal material since it causes the navicular tuberosity to become abnormally flattened and porous. The purpose of this study was to describe the various manifestations of the accessory navicular in dry bone, to present and compare frequency data for several skeletal populations, and to consider questions of laterality and sex bias in trait expression. In total, the skeletons of 497 Danes, 460 Euro-Americans, 300 African Americans, 100 Japanese, and 205 Europeans were examined for the presence of the Type II accessory navicular. Overall frequencies for the five groups ranged from 2% in the African American sample to 5% in the Japanese sample. Since several family pedigrees have documented the accessory navicular as being an inherited skeletal defect, the relatively low frequency found in the present study makes this trait a potentially useful indicator of genetic relatedness within archaeological cemeteries. In addition, the trait was found to occur more often unilaterally than bilaterally and there was nearly equal incidence among males and females.

Sesamoids in tetrapods: the origin of new skeletal morphologies

“…Manners‐Smith, ). Among traumatologists, the accessory navicular syndrome is widely known (Broome & Houghton, ; Bernaerts et al, ; Offenbecker & Case, ; Cheong et al, ). This syndrome involves a congenital accessory bone or cartilage embedded in the tendon of the M. tibialis posterior (see also Müller, ).…”

“…This syndrome involves a congenital accessory bone or cartilage embedded in the tendon of the M. tibialis posterior (see also Müller, ). Three different types of accessory navicular elements have been described: type 1, a separate ossicle embedded within the tendon of the tibialis posterior; type 2, a triangular ossification centre adjacent to the navicular tuberosity and connected by a synchondrosis; and type 3, an enlarged medial horn of the navicular itself, also named the cornuate navicular (Offenbecker & Case, ). We propose that these three types of accessory navicular elements are sesamoids observed at three stages during the attachment/detachment to the navicular foot bone.…”

“…The circles contain three skeletal structures: sesamoid, epiphysis and apophysis. Sesamoids‐to‐epiphyses transformation has reported to be bidirectional (arrows 1 and 2; Bernays, ; Brunner, ; Parsons, ; Pearson & Davin, ; Vaughan & France, ; Offenbecker & Case, ; Eyal et al, ). Changes from epiphyses to apophyses (arrow 3; Parsons, ; Dang et al, ) and from sesamoids to apophyses (arrow 4; Koyama et al, ) have also been reported.…”

Skeletal Kinship Analysis Using Developmental Anomalies of the Foot

“…Many postcranial anomalies are also found among the smaller and less-often-studied bones of the hands and feet, where they may not be noticed even when present. Finally, misinterpretation of some developmental anomalies as resulting from trauma, localised infection, or degenerative joint disease may also contribute to poor reporting (Regan et al, 1999;Case & Burnett, 2012;Offenbecker & Case, 2012).…”

Bioarchaeology and Kinship: Integrating Theory, Social Relatedness, and Biology in Ancient Family Research

“…Scholars continue to make important methodological contributions to the study of kinship by identifying traits potentially useful as indicators of genetic relatedness within skeletal samples (e.g., Offenbecker and Case 2012;Paul and Stojanowski 2015;Villotte et al 2011), comparing the effectiveness of different types of data for identifying biological relatedness (e.g., Adachi et al 2006;Ricaut et al 2010;Velemínský and Dobisíková 2005), and incorporating new analytical techniques (e.g., Gamba et al 2011;Ricaut et al 2006;Usher and Allen 2005;Usher and Weets 2014).…”