Evolutionary anatomical and functional characteristics of the intrinsic shoulder and brachial muscles in the northern anteater (Tamandua mexicana).

Tamandua mexicana is an anteater species native from Mexico to Peru. This species is of great evolutionary interest because it belongs to one of the oldest clades of placental mammals in the American continent. This study aimed to describe the origin, insertion, and arterial supply of the intrinsic shoulder and brachial muscles of T. mexicana. We also compared the masses of the functional groups. Gross dissections were performed on both thoracic limbs of 13 cadavers. ANOVA followed by Tukey's test was used for statistical analyses. The subscapularis muscle presents a hiatus to the common tendon of the caput breve of the biceps brachii and coracobrachialis muscles. A variant accessory muscle, the m. articularis humeri lateralis, was found on the lateral surface of the shoulder joint. M. deltoideus pars acromialis has two bellies. The teres major muscle is perforated by the aponeurotic origin of the m. tensor fasciae antebrachii. The triceps brachii has two capita longi. The caput mediale is fused with the m. anconeus medialis. The caput laterale can have an accessory belly as an anatomical variant. Among the functional groups, a significant difference was found between the elbow extensors and flexors, with the latter having the lowest mass. In conclusion, the intrinsic muscles of T. mexicana presented unique features for the species, as well as arrangements in mass distribution that evidence a possible evolutionary convergence among species of the Superorder Xenarthra.

Anomalous origin of the right subclavian artery in a Neotropical otter (Lontra longicaudis, Olfers-1818).

The Neotropical otter (Lontra longicaudis) is a mustelid distributed geographically from Mexico to Argentina. Anomalous origins of the aortic arch branches are rarely reported in wild carnivorans. Therefore, this study aimed to report the anomalous branching of the aortic arch in one formaldehyde-fixed specimen of L. longicaudis. The aortic arch provided three branches: the bicarotid trunk and the left and right subclavian arteries. The latter passed dorsally to the esophagus toward the right side without a mark of compression at the esophagus. This is the first report of an anomalous origin of the right subclavian artery in L. longicaudis.

Origin and Distribution of the Brachial Plexus in Two Procyonids (Procyon cancrivorus and Nasua nasua, Carnivora).

Procyon cancrivorus and Nasua nasua are two procyonids with different evolutionary adaptations to use their thoracic limbs. Therefore, this study aimed to characterize the differences in the brachial plexus between both species. Five P. cancrivorus and five N. nasua cadavers were used to perform this investigation with the permission of the bioethics committee and environmental license. Gross dissections were performed on the cervical, pectoral, and thoracic limb regions to find the origin and distribution of the brachial plexus. The brachial plexus of both species originated in a variant manner from C5-T1, C5-T2, C6-T1, or C6-T2. All brachial plexus nerves were observed and, interestingly, the musculocutaneous sent a communicating branch to the median nerve medially to the axillary artery, forming an ansa axillaris in both species. An ansa pectoralis was also observed medially to the axillary artery. Additionally, in P. cancrivorus, the musculocutaneous nerve innervates the pronator teres and flexor carpi radialis muscles and communicates with the median nerve at the elbow level to continue as a common trunk at the antebrachium. The brachial plexus has differences between both procyonids, although in both species, it could conserve a primitive arrangement present within the infraorder Arctoidea.

Gross anatomical description of the extrinsic and intrinsic scapular and brachial muscles of Sapajus apella (Linnaeus, 1758).

BACKGROUND: The robust brown capuchin monkey (Sapajus apella) is a South American primate with preferences for arboreal locomotion, which requires specific thoracic limb muscle adaptations. The present investigation studied the gross anatomy of the extrinsic and intrinsic scapular and brachial muscles. METHODS: Gross dissections were performed in both thoracic limbs of four formaldehyde-fixed specimens. RESULTS: Three rhomboideus muscles were present (capitis, cervicis, and thoracis). The trapezius muscle was divided into two parts (cervicis and thoracis). The pectoralis abdominalis and omotransversarius muscles were present. The anconeus muscle was found as an individual muscle or fused to the caput mediale of the triceps brachii muscle. The brachialis muscle had among one and two heads. The anconeus epitrochlearis was absent. CONCLUSION: These muscles of Sapajus apella are adapted for arboreal locomotion and some terrestrial habits, since these have many similarities with other primates with a similar locomotor patterns.

Evolutionary comparative analysis of the extrinsic thoracic limb muscles in three procyonids (Procyon cancrivorus Cuvier, 1798, Nasua nasua Linnaeus, 1766, and Potos flavus Schreber, 1774) based on their attachments and innervation.

The procyonids (Procyon cancrivorus, Nasua nasua and Potos flavus) are Neotropical carnivorans with the ability to climb trees; however, each one has different locomotor preferences. Thereby, P. flavus is highly arboreal, P. cancrivorus is mainly terrestrial with abilities to swim, and N. nasua is also fossorial. These activities not only require movements of the hands but stabilize the thoracic limb, an action performed by the extrinsic muscles. Besides, former descriptions performed in procyonid species have obsolete terms for these muscles, generating confusion about the comparison among species. Thereby, muscle innervation has also been used to support the evolutionary derivation of the muscles. Therefore, this study aimed to describe the attachments and innervations of these muscles in three procyonids. There were intra- and interspecific anatomical variations in the attachments of all extrinsic thoracic limb muscles. However, based on the innervation, several evolutionary derivations in procyonids could be found, such as: the cleidobrachialis muscle derived from the deltoideus muscle; the atlantoscapularis muscle of P. flavus derived from the serratus ventralis cervicis muscle; the pectoralis transversus muscle derived from the pectoralis profundus and superficiales muscles; and the pectoralis abdominalis muscle derived from the cutaneus trunci muscle. Some functions could be associated with locomotor habits, among them a highly developed pectoralis abdominalis in Nasua for its fossorial habits and the atlantoscapularis in Potos for its arboreal and prehensile habits. Thus, the extrinsic muscles in procyonids have evolved for locomotor preferences, but mainly due to their phylogenetic relationship within the family Procyonidae.

Origin and distribution of the brachial plexus in kinkajou (Potos flavus - Schreber, 1774).

The kinkajou (Potos flavus) is a carnivoran adapted for arboreal quadrupedal locomotion along with a prehensile tail. The thoracic limb bones and muscles of this species have been studied, but the knowledge about its nerves is still scarce. This knowledge is necessary to perform several veterinary procedures, and to review the differences among carnivoran species. Thus, the objective of this study was to describe the origin and distribution of the brachial plexus in Potos flavus. Thereby, both brachial plexuses of five specimens were dissected (10). Seven plexuses originated from C6-T2 (70%), whilst three plexuses originated from C5-T2 (30%). Additionally, C6 and C7 formed two cranial trunks, and C8, T1 and T2 formed two caudal trunks. All nerves from the brachial plexus that have been reported in carnivorans were successfully located. In addition, we found one nerve reaching the teres major muscle originating directly from the brachial plexus and not from the axillary nerve as reported in other carnivorans. The brachiocephalic nerve was found partially innervating the cleidobrachialis muscle (50%), but this muscle always was innervated by the axillary nerve. Moreover, one to three subscapular nerves were found, and the musculocutaneous nerve formed two communicating branches (proximal and distal) to the median nerve. However, the distal communicating branch of the musculocutaneous nerve was absent in two specimens (40%). In conclusion, the brachial plexus of P. flavus was differentiated mainly with other carnivorans by a higher contribution from T2, formations of trunks, and one independent nerve to the teres major muscle.

Anatomical, morphometric and radiographic study of the humerus in lesser anteater (Tamandua mexicana Saussure, 1860): terminological and functional analyses.

Tamandua is a neotropical mammal genus that belongs to the superorder Xenarthra. The thoracic limbs of Tamandua have anatomical adaptations that widely differ from other mammals, and there are frequently specimens in wildlife care centers with traumas in their limbs. However, there are few studies describing the radiographic and morphometric anatomy of the humerus in Tamandua, or describing partially the bone reliefs. Thus, the main objective of this study was to describe the characteristics of the humerus of Tamandua mexicana based on gross dissections, radiographies and measurements comparing with other studies in the three Vermilingua genera, and establishing more suitable terminology. Twelve thoracic limbs of six death specimens of Tamandua mexicana were analyzed. The bone reliefs, ligaments, muscles and neurovascular structures related to the humerus were identified, and the suitable terminology to the humerus of Tamandua was established. Morphometric measurements of each bone relief were taken, and the data were statistically analyzed with the Wilcoxon non-parametric test for functional proposes. The humerus of Tamandua has anatomical characteristics mainly to offer greater areas to the muscles that act on the shoulder flexion and hand movements. Even the articular reliefs are lesser than the adjacent non-articular reliefs, the muscles and ligaments are the anatomical structures that give more stabilization to the shoulder and elbow joints. The deltosupracondylar ligament can be partially ossified in older adult specimens, and neurovascular structures pass through the supracondylar foramen. These anatomical characteristics must be accounted for in the radiological diagnosis and surgical approaches.

Gross anatomy of the craniolateral antebrachial muscles in kinkajou (Potos flavus, Carnivora): Intra- and interspecific variants within the family Procyonidae.

The kinkajou (Potos flavus) is a carnivoran that has special morphological adaptations in its thoracic limbs to climb threes and handling food. This study aimed to describe the craniolateral muscles of the antebrachium in P. flavus. Five specimens were used. The extensor carpi radialis longus and brevis were seen as two separate muscles. The extensor carpi ulnaris muscle can present two bellies with different insertions. An extensor digit III muscle was found. The P. flavus has anatomical variants on the craniolateral antebrachial muscles that were previously reported in other procyonids. Thus, those variants are phylogenetically related within the family Procyonidae, except the doubled bellies of the extensor carpi ulnaris muscle which is exclusive of P. flavus.

Evolutionary and terminological analysis of the flexor digitorum superficialis, interflexorii and palmaris longus muscles in kinkajou (Potos flavus) and crab-eating racoon (Procyon cancrivorus).

The kinkajou (Potos flavus) and crab-eating raccoon (Procyon cancrivorus) are carnivores belonging to the family Procyonidae, but both species are characterized by different types of locomotion. Differences can be found in the adaptations that these two species present in the forearm muscles, such as the flexor digitorum superficialis (FDS), palmaris longus (PL) and interflexorii (IF), which have been described confusingly in previous studies. Therefore, the aim of this study was to describe these muscles in both species together with their innervations to carry out an evolutionary and terminological analysis among carnivorans. Both thoracic limbs were dissected from five P. flavus and three P. cancrivorus that had died of natural causes in Wildlife Care Centers. Two PL muscles (m. palmaris longus lateralis, PLL, and m. palmaris longus medialis, PLM) were found in P. flavus, and the IF were the only superficial flexors of the digits, whereas P. cancrivorus presented the IF and two bellies homologous to the two PLs of P. flavus, where the homologous belly of the PLM sent tendons to digits II-IV. Therefore, it was considered as the FDS due to its similarity to other carnivorans, and the lateral belly is the only PL present in P. cancrivorus. The topology, attachments and innervation of these muscles in P. flavus and P. cancrivorus allowed homologies to be established, hypothesizing their evolutionary derivation from the FDS. It also allowed the differences among PL, FDS and IF muscles to be described, concluding that most carnivorans do not have a PL.

Evolutionary adaptations in the flexor digitorum profundus muscle in Tamandua mexicana (Xenarthra, Myrmecophagidae).

The northern tamandua (Tamandua mexicana) is a neotropical mammal of the order Pilosa, suborder Vermilingua, and family Myrmecophagidae. This species has anatomical and functional adaptations in its forelimb for semiarboreal quadrupedal locomotion. Several studies have reported that the medial head of the triceps brachii and flexor digitorum profundus muscles are fused in species belonging to the family Myrmecophagidae. However, there is no reference to the innervation in these. The triceps brachii muscle is commonly innervated by the radial nerve and the flexor digitorum profundus muscle by the ulnar and median nerves. This study aims to describe the gross anatomy of the flexor digitorum profundus muscle in Tamandua mexicana with respect to the shape, origin, insertion, innervation, and arterial supply. Both forelimbs of nine specimens were used, which were dissected from superficial to deep layers. The formalin-fixed caudomedial forearm muscles were weighed, and the weight percentages of individual forearm muscle specimens were calculated. The flexor digitorum profundus had the highest weight among the forearm muscles and consisted of five heads (three humerals, one radial, and one ulnar). These heads were innervated by median and ulnar nerves; therefore, based on the innervation pattern, we concluded that the medial head of the triceps brachii muscle is not fused with the flexor digitorum profundus. Therefore, the flexor digitorum profundus muscle is highly developed in Tamandua and occupies the caudal part of the arm and forearm, which is an evolutionary adaptation that could have occurred during evolution from the common ancestor of Tamandua and Myrmecophaga.

The terminal ventricle of Saguinus leucopus (Primate).

The terminal ventricle is a dilation of the ventricular system located within the spinal cord, which is enveloped in ependymal cells that are involved in the dynamic of the cerebrospinal liquid. In the present study, four Saguinus leucopus specimens were dissected, two males and two females, whose spinal cords were extracted and histologically processed via hematoxylin and eosin stains of cuts at the conus medullaris. The S. leucopus' terminal ventricle was observed at the conus medullaris, and had an average diameter of 241.38 µm. Thus, the presence of the terminal ventricle in the S. leucopus at the level of the conus medullaris was established.

Quantification of the use of eponyms in two Latin American congresses of anatomy.

Eponyms have been part of medical language for many centuries, have put down powerful cultural roots, and continue to be used mainly in the language of medical specialties. The problem with eponymy is that it does not provide any relevant information about what is being studied, which hinders learning and generates communication problems. Ten oral presentations were randomly evaluated, as were all poster presentations made at the II Peruvian Congress on Morphological Sciences and the XV Ibero-Latin American Symposium on Anatomical, Histological, and Embryological Terminology, held in March of 2018 in Lima, Peru. This was done in order to quantify eponym use. Of the 10 oral presentations randomly selected, the eponym use was identified in six (60%). Of the 33 poster presentations made, six (18.18%) used eponyms. In conclusion, eponyms continue to be used indiscriminately in the language of the morphological sciences.

Gross anatomy of the shoulder and arm intrinsic muscles in the white-footed tamarin (Saguinus leucopus - Günther, 1876): Inter- and intraspecific anatomical variations.

BACKGROUND: Saguinus leucopus is a Neotropical primate with an arboreal quadrupedal locomotion pattern, which requires wide movements of the shoulder and arm. This investigation studies the muscles of these regions in order to serve as a basis for clinical and surgical procedures and to compare with other primates. METHODS: Gross dissections of twenty thoracic limbs were performed. RESULTS: The muscles examined were the deltoid, supraspinatus, infraspinatus, subscapularis, teres major, teres minor, coracobrachialis longus, coracobrachialis brevis, biceps brachii, brachialis, triceps brachii, tensor fasciae antebrachii, and anconeus epitrochlearis. The anconeus was absent. The following variants were found: an accessory head of the biceps brachii, the unilateral absence of the short head of the biceps brachii, an accessory head of the coracobrachialis longus, and one infraspinatus muscle innervated by the axillary nerve. CONCLUSIONS: These muscles are adapted to quadrupedal locomotion and can have inter- and intraspecific variations in their attachments and innervation.

Anatomical and radiographic study of the scapula in juveniles and adults of Tamandua mexicana (Xenarthra: Myrmecophagidae).

Tamandua mexicana is a mammal of the superorder Xenarthra geographically located between Mexico and Peru that remains insufficiently studied. These species are characterized by their movement, resting, and eating of termites and ants in arboreal and terrestrial environments, and therefore, their thoracic limbs have been adapted morphologically to move in these environments. Tamandua mexicana is a species constantly threatened by different causes, and their thoracic limbs can be affected in the scapular and shoulder regions as a result; therefore, specific anatomical knowledge of the scapula allows for better clinical procedures, surgical approaches, radiological diagnosis and muscular reconstructions in extinct species of anteaters. The main objective of this study was to report the anatomical and radiographic features of the scapula in juvenile and adult specimens of T. mexicana. Gross dissections and radiographic study were performed in six cadavers. The scapula had large differences compared with other mammals, such as two spines, a foramen for the suprascapular nerve, a long acromion, a cranial transverse scapular ligament and caudolateral fossa for the origin of the muscles teres major, tensor fasciae antebrachii and subscapular. In juvenile specimens, a scapular cartilage, an acromial cartilage, craniomedial and caudolateral coracoscapular ligaments forming the foramen for the suprascapular nerve, and progressive ossification of those ligaments and the cranial transverse scapular ligament were observed. These findings were corroborated by radiography; therefore, these characteristics change with age. The bony reliefs of the scapula of T. mexicana corroborate the specialization of the shoulder in this species.

Incidence of sternalis muscle in the Caldas population (Colombia): anatomical variations / Incidencia del músculo esternal en la población de Caldas (Colombia): variaciones anatómicas

The musculus sternalis is an anatomical variant that occurs in 3-8 % of the world population and its incidence is higher in women. It can be found unilaterally or bilaterally and is located in the anterior wall of the thorax, where its fibers run parallel to the sternum and superficial to the medial part of the pectoralis major muscle. The main objective of this study was to quantify the incidence of musculus sternalis in the population of Caldas (Colombia) and, therefore, 68 cadavers of adult individuals were used during a period of twenty years to determine the incidence of this muscle and describe its anatomical characteristics. Two cadavers had this muscle, which was equivalent to 2.94 % of the sample, where one was located unilaterally and in other bilaterally. In the case of unilateral presence, the muscle presented an oblique direction thatdoes not coincide with any subtype of the classification given for these muscles. In bilateral presentation, both muscles were continuous at their upper ends with the respective sternocleidomastoid muscle. In addition, the right musculus sternalis had a digastric shape, which also does not coincide with any subtype of the classification.

El músculo esternal es una variante anatómica que se presenta entre el 3 % y 8 % de la población mundial y su incidencia es mayor en mujeres. Puede hallarse de manera unilateral o bilateral y se localiza en la pared anterior del tórax, donde sus fibras corren paralelas al esternón y superficial a la región medial del músculo pectoral mayor. El objetivo del presente estudio fue cuantificar la incidencia del músculo esternal en la población de Caldas (Colombia). Fueron revisados 68 cadáveres de individuos adultos durante un lapso de doce años, con el fin de determinar el grado de presencialidad del músculo y sus características anatómicas. Dos cadáveres, que equivale al 2,94 % de la muestra, presentaron el músculo esternal, uno de manera unilateral y el otro bilateral, a los cuales se les hizo una descripción anatómica detallada. En la presentación unilateral, el músculo presentó una dirección oblicua que no coincide con ningún subtipo de la clasificación dada para estos músculos. En la presentación bilateral, ambos músculos se continúan por su extremo superior con el respectivo músculo esternocleidomastoideo. Además, el músculo esternal derecho tiene una configuración digástrica, que tampoco coincide con ningún subtipo de la clasificación.

Gross anatomical adaptations of the craniolateral forearm muscles in Tamandua mexicana (Xenarthra: Myrmecophagidae): development of accessory muscles and rete mirabile for its arterial supply.

The northern tamandua (Tamandua mexicana) is a xenarthran mammal with a distribution from Mexico to Peru. This species arrives to wildlife care centres due to illegal trafficking and attacks by domestic dogs, both of which are situations where the northern tamandua's thoracic limbs (forelimbs) can be affected. As such, it is necessary to have anatomical studies that allow us to perform better medical and surgical procedures. Among these, studies about the musculoskeletal system also aid in the muscular reconstructions of extinct species. The aim of this study was to characterize the craniolateral muscles of the forearm in Tamandua mexicana and compare them with other Xenarthrans to determine their gross adaptations. Six dead specimens were used, and none were sacrificed for the purpose of this investigation. In five specimens, arterial repletion was done. Four were fixed with 10% formaldehyde and 5% glycerin, and two were dissected in fresh. All were dissected in the Veterinary Anatomy Laboratory of the Universidad del Tolima. The weights of the muscles from seven forearms were taken and divided in three functional groups for comparison with non-parametric statistics. Two muscular groups were found: one superficial formed by the brachioradialis, brachioradialis accesorius, extensor carpi radialis, extensor digitorum communis, extensor digitorum lateralis and extensor carpi ulnaris; and one deep muscular group formed by the supinator, extensor digiti III et IV, abductor digiti I longus, and extensor digiti I et II. They were supplied by different branches of the cranial interosseous, transverse cubital and superficial brachial arteries, which had the shape of rete mirabile; and all muscles were innervated by the deep branch of the radial nerve. The presence of the brachioradialis accesorius muscle in this species allows its hand to remain in semi-supination when it is mobilized in a quadrupedal manner. It must also support elbow flexion together with the action of the brachioradialis and the extensor carpi radialis muscles. All the antebrachial digital muscles sent tendons for the digit III making it the most functional for different grip activities such as climbing trees and searching for its food, however, the most strength was directed to supination and carpal extension, and therefore also to the flexion of the elbow.

Inconsistencias de la terminologia anatomica: la vértebra cervical 1 nombrada con el epónimo atlas / Inconsistencies of the terminologia anatomica: first cervical vertebra named with the eponim atlas

La primera vértebra cervical establece una articulación sinovial con los cóndilos del occipital, sin que haya de por medio disco fibrocartilaginoso. Esta articulación es importante para la anatomía funcional del cuello porque, además de soportar el peso de la cabeza en los humanos, permite movimientos de flexión, extensión e inclinación lateral. La primera vértebra es conocida en la Terminologia Anatomica y en la Nomina Anatomica Veterinaria con el nombre de Atlas [C1]. El nombre de Atlas, asignado a la primera vértebra cervical, fue tomado de uno de los titanes de la mitología griega condenado por el dios Zeus a soportar el cielo con sus manos, cabeza y hombros, y que en términos figurativos es la que sostiene el mundo craneal. Sorprende que en el libro oficial de la Terminologia Anatomica y en el de la Nomina Anatomica Veterinaria se mantenga este epónimo por una simple tradición, constituyéndose en una vergonzosa contradicción que debe ser corregida y eliminada.

The first cervical vertebra establishes a synovial joint with the occipital condyles, without having a fibrocartilaginous disc. This joint articulation is important for the functional anatomy of the neck, because in addition to supporting the weight of the head in humans, it allows movements of flexion, extension and lateral inclination. The first cervical vertebra is known in the Terminologia Anatomica and the Nomina Anatomica Veterinaria with the name of Atlas [C1]. The name Atlas, assigned to the first cervical vertebra, was taken from one of the titans of Greek mythology condemned by the god Zeus to support the world with the hands, head, and shoulders, so in figurative terms said vertebra is the one that sustains the cranial world. It is surprising that in the official book of the Terminolgia Anatomica and in the Nomina Anatomica Veterinaria this eponymous is maintained by a simple tradition, constituting a shameful contradiction that must be corrected and eliminated.

Morphometric, anatomic and radiographic study of the scapula in the white-footed tamarin (Saguinus leucopus): report of scapular cartilage and one variation in cranial (superior) transverse scapular ligament.

The white-footed tamarin (Saguinus leucopus) is an endangered endemic primate of Colombia, mainly due to the deforestation of its habitat and illegal trade, which generates a high incidence of these animals in wildlife care centres. Musculoskeletal system disorders in S. leucopus are one of the most common diseases and therefore the aim of this study was to contribute to the morphologic studies with a morphometric, anatomic and radiographic description of the scapula in this species to provide a basis for medical interventions, surgical approaches, radiologic diagnoses and comparative functions of this bone. Gross dissections of each scapular region were made in eight specimens without a diagnosis of osteomuscular disease. These specimens died from natural cases in the wildlife care centres of the Corporación Autónoma Regional de Caldas (CORPORCALDAS); after necropsy their carcasses were fixed with 10% formaldehyde, 5% mineral oil and 1% phenic acid in these centres over the course of at least 1 week. X-rays of the scapula were taken in the small animal clinic of the Universidad del Tolima, and morphometric data of the scapulae were obtained with a digital calliper. The scapula of the white-footed tamarin was a flat triangular bone with a deep scapular notch in its cranial margin, where there was a cranial transverse scapular ligament that was absent in two specimens. The coracoid process was highly developed, medially covering the humeral joint. The dorsal margin was covered by the scapular cartilage, which was highly developed in the caudal angle. In the dorsal fourth of the caudal margin, there was a surface from which the m. teres major originated. The lateral surface had a scapular spine with a long hamatus process of the acromion until the lateral part of the humeral joint. The infraspinatus fossa was wider than the supraspinous fossa. On the costal surface, the subscapular fossa was formed by three subscapular lines and one subscapular ridge, the latter helping to form the surface for the m. teres major. In the two radiographic views, caudocranial to the scapula and dorsoventral to the thorax, the scapular spine, acromion, coracoid process, scapular incisura, supraglenoid tubercle, caudal margin, subscapular ridge, and the joints with the clavicle and the humerus could be observed. The scapula of the white-footed tamarin presented bony reliefs that share characteristics with other primates but also with domestic mammals due to its quadrupedal locomotion, which allowed us to correlate its morphologic adaptation with its quadrupedal arboreal displacement.

Anatomical variations of the caudomedial antebrachial muscles in the crab-eating fox (Cerdocyon thous) / Variaciones anatómicas de los músculos caudo-mediales del antebrazo del zorro perruno (Cerdocyon thous)

The crab-eating fox (Cerdocyon thous) is a wild canid distributed in South America, which is susceptible to traumas caused by captors, accidents on roads, and traps. Due to these events their thoracic limbs can be involved at the level of the forearm, therefore, knowledge of the gross anatomy of its muscles is important in order to develop clinical and surgical procedures at this level compared with the domestic dog. The main objective of this investigation was report the intra and interspecific anatomical variations of the caudomedial forearm muscles in Cerdocyon thous in comparison mainly with the domestic dog. Six dead specimens from wildlife care centres of CORPOCALDAS were used. These were fixed with a solution of formaldehyde, mineral oil and phenic acid. Both thoracic limbs of each specimen were dissected from superficial to deep, emphasizing the caudomedial part of the forearm in order to review the anatomical characteristics of each muscle. These muscles were similar to those reported in the domestic dog, but some variations were observed such as the innervation of the pronator teres muscle by the musculocutaneous nerve in a specimen unilaterally; the formation of an accessory muscle from the ulnar head of the flexor carpi ulnaris muscle in most specimens; and the vestigial presence of the anconeus epitrochlearis muscle in a specimen bilaterally.

El zorro perruno (Cerdocyon thous) es un cánido silvestre distribuido en Sudamérica, el cual es susceptible a traumas causados por captores, accidentes en carreteras y trampas, donde pueden verse involucrados sus miembros torácicos a nivel del antebrazo, por lo tanto, conocer la anatomía de sus músculos es importante, ya que ésta servirá como base en la realización de procedimientos clínicos y quirúrgicos a este nivel en comparación con el perro doméstico. El objetivo principal de esta investigación fue reportar las variaciones anatómicas intra e interespecíficas de los músculos caudo-mediales del antebrazo de C. thous en comparación principalmente con el perro doméstico. Se utilizaron seis especímenes muertos bajo la jurisdicción de CORPOCALDAS. Estos se fijaron con una solución en mezcla de formaldehído, aceite mineral y ácido fénico. Se diseccionaron de superficial a profundo los dos miembros torácicos de cada espécimen, haciendo énfasis en la parte caudo-medial del antebrazo para revisar las características anatómicas de cada músculo, las cuales fueron similares a las reportadas al perro doméstico, pero se observó en un espécimen de manera unilateral la inervación al músculo pronador teres por parte del nervio musculocutáneo; en la mayoría de especímenes se observó la formación de un músculo accesorio a partir de la cabeza ulnar del músculo flexor ulnar del carpo; y en un espécimen la presencia vestigial del músculo ancóneoepitroclear.

Anatomic description of the palmaris longus muscle and report of variant nerve supply in the white-footed tamarin (Saguinus leucopus Günther, 1876).

The gross anatomy of the palmaris longus muscle in 12 specimens of Saguinus leucopus was studied by dissection. This muscle was constant and unipennate, originated in the medial epicondyle of the humerus; inserted onto flexor retinaculum and palmar aponeurosis; and innerved by the median nerve, and in one case, together with the ulnar nerve. This is the first report of double innervation for this muscle in primates.