Topographical Anatomy of the Rhesus Monkey (Macaca mulatta)—Part I: Thoracic Limb

Abstract

Since the rhesus monkey (Macaca mulatta) is genetically closely related to man, it is generally accepted that its anatomy and physiology are largely similar to that of humans. Consequently, this non-human primate is most commonly used as a model in biomedical research. Not only the validation of the obtained research data, but also the welfare of the captive rhesus monkeys are subject to thorough anatomical knowledge of this species. Unfortunately, anatomical literature on the rhesus monkey is scarce, outdated, and hardly available at present. Furthermore, its anatomy is only illustrated by means of line drawings or black-and-white photographs. Thus, the aim of this study was to describe the anatomy of the thoracic limb of the rhesus monkey topographically, studying the various anatomical structures in relation to each other. In this manuscript, the anatomy of the thoracic limb is described per region. The structures that are visible on the different layers, from the superficial to the deepest layer, are described both in text and in numerous color images. As expected, the anatomy of the rhesus monkey is almost identical to human anatomy. However, some striking differences have been identified. This supports the necessity for an extensive publication on the anatomy of the rhesus monkey

Muscle anatomy is reflected in the spatial organization of the spinal motoneuron pools

“…Additionally, macaques typically have two heads of the coracobrachialis and a single head of the flexor digitorum profundus, while humans have a single coracobrachialis and the flexor digitorum profundus is accompanied by the flexor pollicis longus. Macaques also have the additional dorsoepitrochlearis muscle, which functions similarly to the triceps brachii 37 , but has actually found to limit the range of shoulder abduction in humans with this supernumerary muscle present 38 . Despite these anatomical differences, we use macaques for comparison here due to their ability to perform similar movements to humans, for example, the fractionated finger movements, and the existence of direct corticomotoneuronal projections unlike other species 39 – 41 .…”

Osteology of the Hamadryas Baboon (Papio hamadryas)

“…Cranial anatomy of the baboon is illustrated by Trevor-Jones [33] and [34]. Furthermore, we made use of our previous works on the anatomy of the marmoset (Callithrix jacchus) and rhesus monkey (Macaca mulatta) to identify the numerous anatomical structures in the baboon by means of comparative anatomy between primate species [35][36][37][38][39].…”