The wall of the diaphragm can be affected by congenital or acquired alterations which allow the passage of viscera between the abdominal and chest cavities, allowing the formation of a diaphragmatic hernia. We characterized morphology and performed biometrics of the diaphragm in the common squirrel monkey Saimiri sciureus. After fixation, muscle fragments were collected and processed for optical microscopy. In this species the diaphragm muscle is attached to the lung by phrenopericardial ligament. It is also connected to the liver via the coronary and falciform ligaments. The muscle is composed of three segments in total: 1) sternal; 2) costal, and 3) a segment consisting of right and left diaphragmatic pillars. The anatomical structures analyzed were similar to those reported for other mammals. Histological analysis revealed stable, organized muscle fibers with alternation of light and dark streaks, indicating transverse striation.

Callithrix penicillata é um primata não humano endêmico no Brasil, amplamente utilizado para estudos biomédicos, porém, pouco se conhece quanto à anatomia desses indivíduos, incluindo aspectos vasculares. Assim, objetivamos descrever o arco aórtico dessa espécie, a fim de corroborar tanto estudos comparados quanto ensaios hemodinâmicos para modelos experimentais. Foram avaliados cinco C. penicillata, que apresentaram dois tipos distintos de angioarquitetura do arco aórtico, sendo um comumente encontrado em outros mamíferos, e outro em similaridade com Saguinus niger, sugerindo que tal padrão possa ter relação com o fato de ambas as espécies pertencerem à Família Callithrichidae.