%0 Journal Article
%T Comparative Triceps Surae Morphology in Primates: A Review
%A Jandy B. Hanna
%A Daniel Schmitt
%J Anatomy Research International
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/191509
%X Primate locomotor evolution, particularly the evolution of bipedalism, is often examined through morphological studies. Many of these studies have examined the uniqueness of the primate forelimb, and others have examined the primate hip and thigh. Few data exist, however, regarding the myology and function of the leg muscles, even though the ankle plantar flexors are highly important during human bipedalism. In this paper, we draw together data on the fiber type and muscle mass variation in the ankle plantar flexors of primates and make comparisons to other mammals. The data suggest that great apes, atelines, and lorisines exhibit similarity in the mass distribution of the triceps surae. We conclude that variation in triceps surae may be related to the shared locomotor mode exhibited by these groups and that triceps surae morphology, which approaches that of humans, may be related to frequent use of semiplantigrade locomotion and vertical climbing. 1. Introduction From Aristotle¡¯s thoughts in De Motu Animalium [1], to Borelli¡¯s [2] comprehensive review of biomechanics in the 1600s, to Muybridge¡¯s [3] original documentation of gaits in horses around the turn of the last century, animal movement has been a vibrant and productive area of research providing insights into critical aspects of form-function relationships and selection pressures on limb and body design in many vertebrates, including primates. In addition to capturing photographic plates of the different gaits of the horse, Muybridge also took stop motion images of other mammals, including a nonhuman primate. His famous collection of plates and prose, published in 1887, was the first available to researchers interested in animal locomotion [3] and spawned a new generation of scientists interested in locomotion. Following Muybridge¡¯s observation that the baboon ¡°disregards the law governing the walk¡± (3£¿:£¿30), multiple researchers created hypotheses concerning primate locomotor evolution, which were based on observed differences between primate and nonprimate locomotion (e.g., [4, 5]). For example, building on Muybridge¡¯s observations on footfall, in which he argued for a differential functional role of the forelimb and hindlimb in primates, forty years later, De la Croix [6] commented on the unique aspects of what he called ¡°the pithecoid gait¡± (6£¿:£¿53 and Figure 3 therein), which he argued was ¡°the gait used by the early ancestors of man.¡± (6£¿:£¿53, referring to [7]). These early scientists laid the foundations for research in primate locomotor evolution. Since then researchers have been
%U http://www.hindawi.com/journals/ari/2011/191509/