In Primates, the clavicle is intimately involved in two very distinctive behaviors: arborialism and/or handling. Although infrequently studied, clavicular morphology may be a crucial element to determining upper limb locomotor behavior, not only among Primates, but among the five orders of Theria (Primates, Chiroptera, Insectivora except Potamogale, Dermoptera, and Tubilidentata) that possess a complete bone (Lessertisseur and Saban, 1967 Schmidt et al., 2002). Of the bones, the clavicle has been considerably less studied from a comparative perspective than has the humerus and scapula. In Primates, the shoulder complex includes 3 bones (scapula, clavicle, and humerus), more than 20 muscles (the exact number depending on the particular species), and 4 joints working together. The use of clavicular curvature analysis offers a new dimension in assessment of the functional morphology of the clavicle and its relationship to the shoulder complex. Curvatures in cranial view relate information regarding the parameters of arm elevation while those in dorsal view offer insights into the position of the scapula related to the thorax. The last group includes only modern humans, whose clavicles show only the inferior curvature, which is less pronounced than that which exists in monkeys. The third group includes only Hylobates, whose clavicles possess only the superior curvature. The second included monkeys, whose clavicles have an inferior curvature much more pronounced than the superior one. The first group is characterized by two curvatures, an inferior and a superior (Apes, Spider monkeys). Clavicle curvatures projected on the dorsal plane could be placed into four groups. One group exhibited an external curvature considerably more pronounced than the internal one ( Gorilla, Papio) a second group was characterized by an internal curvature much more pronounced than the external one ( Hylobates, Ateles) and a third group contained those with the two curvatures equally pronounced ( Pan, Homo, Pongo, Procolobus, Colobus). Results showed that in cranial view, three morphologies can be defined. Methods have included the assessment of clavicular curvatures projected on two perpendicular planes that can be assessed overall as cranial and dorsal primary curvatures. The present study compares clavicular morphology among different extant primates. In spite of its importance for movements of the upper limbs, the clavicle is an infrequently studied shoulder bone.
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