Morphological and evolutionary insights into the keystone element of the human foot's medial longitudinal arch.

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Sorrentino, Rita; Carlson, Kristian J; Orr, Caley M; Pietrobelli, Annalisa; Figus, Carla; Li, Shuyuan; Conconi, Michele; Sancisi, Nicola; Belvedere, Claudio; Zhu, Mingjie; Fiorenza, Luca; Hublin, Jean-Jacques; Jashashvili, Tea; Novak, Mario; Patel, Biren A; Prang, Thomas C; Williams, Scott A; Saers, Jaap P P; Stock, Jay T; Ryan, Timothy; Myerson, Mark; Leardini, Alberto; DeSilva, Jeremy; Marchi, Damiano; Belcastro, Maria Giovanna; Benazzi, Stefano
Year of Publication: 2023
Journal: Commun Biol
Volume: 6
Issue: 1
Pagination: 1061
Date Published: 2023 Oct 19
Publication Language: eng
ISSN: 2399-3642
Keywords: Adult, Animals, Flatfoot, Foot, Fossils, Hominidae, Humans

The evolution of the medial longitudinal arch (MLA) is one of the most impactful adaptations in the hominin foot that emerged with bipedalism. When and how it evolved in the human lineage is still unresolved. Complicating the issue, clinical definitions of flatfoot in living Homo sapiens have not reached a consensus. Here we digitally investigate the navicular morphology of H. sapiens (living, archaeological, and fossil), great apes, and fossil hominins and its correlation with the MLA. A distinctive navicular shape characterises living H. sapiens with adult acquired flexible flatfoot, while the congenital flexible flatfoot exhibits a 'normal' navicular shape. All H. sapiens groups differentiate from great apes independently from variations in the MLA, likely because of bipedalism. Most australopith, H. naledi, and H. floresiensis navicular shapes are closer to those of great apes, which is inconsistent with a human-like MLA and instead might suggest a certain degree of arboreality. Navicular shape of OH 8 and fossil H. sapiens falls within the normal living H. sapiens spectrum of variation of the MLA (including congenital flexible flatfoot and individuals with a well-developed MLA). At the same time, H. neanderthalensis seem to be characterised by a different expression of the MLA.

DOI: 10.1038/s42003-023-05431-8
Alternate Journal: Commun Biol