GROSS ANATOMY AND SURGICAL APPROACH TO THE HUMERAL SHAFT IN GIANT ANTEATER (MYRMECOPHAGA TRIDACTYLA).

Anteater forelimbs are distinguished morphologically from domestic animals, especially due to their unique movement and their natural habits. A knowledge of the pectoral limb anatomy and the proper surgical approach are fundamental to success in osteosynthesis and other surgeries. This study aimed to describe the muscles and neurovascular structures of the pectoral limb and the surgical approach to the humeral shaft of the giant anteater ( Myrmecophaga tridactyla ). Dissections of the forelimbs of seven cadavers were performed to identify the major muscles and neurovascular structures. Three of these animals' contralateral forearms were used to simulate the surgical approach to the humeral shaft. Some specific characteristics of the muscle morphology were biceps muscle had two heads, triceps muscle had three heads, and there was an olecranon-epicondylar muscle. To expose the shaft of the humerus, it was necessary to incise the superficial pectoral muscle and separate the heads of the biceps muscle. Due to the anatomical characteristics of the humerus, the craniomedial approach was the most appropriate because it accommodated the anatomical peculiarities of the giant anteater.

SKELETAL MORPHOLOGY OF THE FORELIMB OF MYRMECOPHAGA TRIDACTYLA.

Anteater forelimbs are morphologically adapted to obtain food and to provide defense and locomotion. Four species are known, but there are few anatomical studies presenting the morphologic features of each species. The aim of this study was to describe the skeletal morphology of the giant anteater (Myrmecophaga tridactyla) forelimb. Pictures and schematic drawings of six cadavers were created to show the bone morphology. In addition, radiographs and computed tomographs were obtained. The skeletal structure of the forelimb had several notable anatomical features. The scapula had two spines, with apparent differences between infant and adult animals. The humerus had a pectoral ridge, a pectoral tubercle, and a pronounced medial epicondyle that represent the origins of muscles important for fossorial activity. The radius had cranial, lateral, and caudal ridges that became more prominent in older animals, and the distal condyle joint provided enhanced support of the dorsal articulation for the manus. Knowledge of the bone morphology of the forelimb generates a better understanding of giant anteater habits and helps in the diagnosis of skeletal abnormalities and in the routine medical assessment of this species.