The present study describes the flexor and extensor muscles in Cebus libidinosus' forearm and compares them with those from humans, chimpanzees and baboons. The data is presented in quantitative anatomical indices for similarity. The capuchin forearm muscles showed important similarities with chimpanzees and humans, particularly those that act on thumb motion and allow certain degree of independence from other hand structures, even though their configuration does not enable a true opposable thumb. The characteristics of Cebus' forearm muscles corroborate the evolutionary convergence towards an adaptive behavior (tool use) between Cebus genus and apes.

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SUMMARY:In 2003, the UFG Faculty of Medicine, to revamp its educational project, reduced the hourly load of some subjects, among them those of anatomy, which in general leads to eliminate the practice of dissection. This practice is essential for the basic training of students, being then used in other sciences such as pathology. The objective of this study was to compare and link data between groups that made or did not make dissection after the anatomy course. Questionnaires were issued to 86 medical students from the UFG Faculty of Medicine, and from these, 10 made dissection and 76 did not. Analyzing the answers, it was found that both groups recognize the importance of this practice for the knowledge of the anatomy discipline and for future disciplines or their profession. It follows that dissection could help in the consolidation of post-modern paradigm in medical education since it improves the attention and learning of students.

RESUMO.-[Anatomia comparativa dos nervos da coxa de Cebus libidinosus (Rylands et al., 2000).]Primatas não-humanos têm constituído um importante grupo entre os animais submetidos a vários estudos. Estudos etológi-cos, evolutivos e paleontológicos revelaram alterações das estruturas anatômicas ligada à evolução dos primatas, considerado em estudos sobre a anatomia comparativa entre Cebus libidinosus e outros primatas neotropicais ou provenientes do Velho Mundo, e as modalidades de conhecimento sobre sua anatomia pode representar um fator importante para a sua preservação e proteção quando os animais são levados às clínicas veterinárias após acidentes ou doenças. Em termos de importância veterinária, ás vezes esses animais chegam na clínica médica veteriná-ria após acidentes, necessitando de cirurgia ou tratamento clínico, mas os poucos dados disponíveis sobre a anatomia tem dificultado o procedimento correto. A principal justificativa para os estudos sobre C. libidinosus é devido a pouca informação sobre sua anatomia na literatura cientí- Non-human primates have constituted an important group among animals subjected to various studies. Ethological, evolutionary and paleontological studies have revealed changes in anatomical structures linked to the evolution of primates, considered in studies on the comparative anatomy between Cebus libidinosus and other neotropical monkeys or those from the Old World, and the detailed knowledge on their anatomy may represent an important factor for their preservation and protection when the animals are brought to veterinary clinics after accidents or illnesses. In terms of veterinary importance, sometimes these animals arrive in the veterinary medical clinics after accidents, needing surgery or clinical treatment, but the little data available on anatomy has impaired the correct proceedings. The main justification for studies on C. libidinosus, is due to little information about the anatomy related to C. libidinosus in Brazilian and worldwide scientific literature. In this study, the distribution, enervation and path of the femoral and sciatic nerves of the pelvic limb (thigh) of C. libidinosus were studied and these results were compared with literature on the anatomy of humans, chimpanzees and baboons. In general, the enervation model of the four primates is identical, but in specific terms, the differences in enervations indicate evolution convergence closer to the branch of baboons in the evolutionary tree, and these data corroborate other comparative studies in relation to the same primates to vessels, muscles and nerves. In conclusion, the nerve organization in the thigh of C. libidinosus is identical to baboon, chimpanzee and homo, but more similar to baboon. The specific differences found indicate an ancient phylogenic origin to C. libidinosus and baboons (data corroborated by other studies). Roqueline A.G.M.F. fica no Brasil e no mundo. Neste trabalho, a distribuição, inervação e os trajetos dos nervos femoral e isquiático do membro pélvico (coxa) de C. libidinosus for...

Capuchin monkeys present a wide variety of manipulatory skills and make routine use of tools both in captivity and in the wild. Efficient handling of objects in this genus has led several investigators to assume near-human thumb movements despite the lack of anatomical studies. Here we perform an anatomical analysis of muscles and bones in the capuchin hand. Trapezo-metacarpal joint surfaces observed in capuchins indicate that medial rotation of metacarpal I is either absent or very limited. Overall, bone structural arrangement and thumb position relative to the other digits and the hand’s palm suggest that capuchins are unable to perform any kind of thumb opponency, but rather a ‘lateral pinch’ movement. Although the capuchin hand apparatus bears other features necessary for complex tool use, the lack thumb opposition movements suggests that a developed cognitive and motor nervous system may be even more important for high manipulatory skills than traditionally held.

The anatomical features observed favor quadrupedal locomotor behaviors on the ground and in arboreal environments. Japanese monkeys, rhesus monkeys, and bearded capuchins, which share more primitive characteristics in their arm muscles, present features that favor both arboreal and quadrupedal locomotor behaviors, whereas apes, mainly Pan and Gorilla, which spend more time on the ground, present more quadrupedal specializations.

The palmaris longus is considered a phylogenetic degenerate metacarpophalangeal joint flexor muscle in humans, a small vestigial forearm muscle; it is the most variable muscle in humans, showing variation in position, duplication, slips and could be reverted. It is frequently studied in papers about human anatomical variations in cadavers and in vivo, its variation has importance in medical clinic, surgery, radiological analysis, in studies about high-performance athletes, in genetics and anthropologic studies. Most studies about palmaris longus in humans are associated to frequency or case studies, but comparative anatomy in primates and comparative morphometry were not found in scientific literature. Comparative anatomy associated to morphometry of palmaris longus could explain the degeneration observed in this muscle in two of three of the great apes. Hypothetically, the comparison of the relative length of tendons and belly could indicate the pathway of the degeneration of this muscle, that is, the degeneration could be associated to increased tendon length and decreased belly from more primitive primates to those most derivate, that is, great apes to modern humans. In conclusion, in primates, the tendon of the palmaris longus increase from Lemuriformes to modern humans, that is, from arboreal to terrestrial primates and the muscle became weaker and tending to be missing.

RESUMO. Este trabalho utilizou 8 espécimes adultos de Cebus apella para caracterização anatômica de músculos do antebraço. Os animais foram doados pelo Instituto Brasileiro de Meio Ambiente e Recursos Naturais Renováveis (Ibama), de Sete Lagoas, Estado de Minas Gerais, Brasil, e sacrificados segundo as recomendações do Colégio Brasileiro de Experimentação Animal (Cobea). O trabalho foi aprovado pelo comitê de ética da UFU. Foram estudados os músculos (1) pronador quadrado, (2) flexor profundo dos dedos e (3) flexor longo do polegar. Em relação aos humanos, os músculos profundos do antebraço de Cebus apella apresentaram características gerais comuns, mas com algumas diferenças na forma, na vascularização e na inervação, diferenças que devem refletir as especializações funcionais daqueles músculos entre as duas espécies. O músculo flexor profundo do polegar privilegia a habilidade de movimentação dos dedos em humanos, e a força da mão em Cebus apella mostra-se necessária nessa espécie, em função de seus hábitos arbóreos.Palavras-chave: anatomia, Cebus apella, primatas, músculos do antebraço.ABSTRACT. Anatomical study of the forearm deep muscles in Cebus apella (Linnaeus, 1766). Eight adult specimens of Cebus apella were used for anatomical muscles characterization. The animals were donated by the Brazilian Institute of Environment and Recyclable Natural Resources (Ibama -Instituto Brasileiro de Meio -Ambiente), from Sete Lagoas, state of Minas Gerais, Brazil, and sacrificed according to the recommendations of Brazilian College of Animal Experimentation (Cobea -Colégio Brasileiro de Experimentação Animal). This work was approved by ethics committee from UFU (Federal University of Uberlândia). The muscles (1) squared pronator, (2) deep fingers flexor and (3) long thumb flexor were studied. In human beings, the deep muscles of Cebus apella have some general common characteristics, but differ in form, vascularization and innervation. These differences should reflect the functional specialization of those muscles between the two species. The long thumb flexor muscle is important for human beings' fingers movement since the force of hand in Cebus paella is a necessary characteristic to this species, according to its arboreous habit.