https://onlinelibrary.wiley.com/doi/10.1002/ajpa.70018
Enthesis Size and Hand Preference: Asymmetry in
Humans Contrasts With Symmetry in Nonhuman Primates
Abstract
Objectives
Humans display species-wide right-hand preference
across tasks, but this pattern has not been
observed at comparable levels in nonhuman primates,
suggesting the behavior arose after the
panin-hominin split. Muscle attachment sites
(entheses) are used to infer soft tissue anatomy
and reconstruct behaviors within skeletal
populations, but whether entheseal size asymmetry
can reflect hand preference remains unclear. If
entheseal asymmetry is linked to hand preference,
we expect to see greater asymmetry in human hands,
where hand preference is more pronounced, compared
to nonhuman primates. We tested for bilateral
asymmetry in the size of the opponens pollicis
muscle flange using a sample of humans and
catarrhine primates to determine if enthesis
development can be a reliable indicator of hand
preference.
...
Results
We found right-directional asymmetry for humans;
no significant differences are observed for
Hylobates, Macaca, and Gorilla.
Conclusion
The opponens pollicis enthesis shows right/left
hand bias in humans. The lack of significant
asymmetry in nonhuman primates suggests
entheseal development in these species does not
reflect the same level of hand preference
observed in humans. Nonhuman primates can serve
as a baseline for studying enthesis asymmetry
based on the size of the opponens pollicis
enthesis.
"Conversely, other primates do not exhibit
species-level, or even population-level,
handedness in wild populations, and only a weak
bias (approximately 65%) in some captive
populations (Hopkins et al. 2011), suggesting
the species-level right-hand preference in
humans arose after the panin-hominin split
(Stephens et al. 2016). Lateralized hand use
in humans has been linked to important
evolutionary milestones, including the advent
of stone tool use and manufacture and the role
that possible visuo-cognitive functional
asymmetries played in the rise of manual
dexterity within the hominin lineage
(Williams-Hatala et al. 2016; Stephens
et al. 2016)."
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