Arrangement and prevalence of branches in the external carotid artery in humans

The external carotid artery originates branches to face structures. The superior thyroid, lingual and facial arteries are originated from this vessel as artery trunks or separately. The aim of this study was to determinate the arrangement frequency of these artery branches. For this, thirty six (36) hemi-heads of adult cadavers from both genders were studied. The anatomic parts were fixed in 10% of formalin and dissected. The superior thyroid, lingual and facial arteries were analyzed in terms of their origins. The superior thyroid, lingual and facial arteries originated separately from the external or common carotid artery in 77.8% of the cases. A linguofacial trunk was observed in 19.9% of the cases and a thyrolingual trunk in 2.8%. A thyrolinguofacial trunk was not observed. In 51.2% cases the superior thyroid artery originated directly from the external carotid artery, in 45.3% from the bifurcation of the common carotid artery, and in 3.5% from the common carotid artery. Thus, the superior thyroid, lingual and facial arteries more frequently showed a separate origin from the external or common carotid artery. Among the combined artery trunks, the linguofacial trunk was most frequently observed, followed by the thyrolingual trunk. The superior thyroid artery originated more frequently from the external or common carotid artery; however, it also could emerge from the bifurcation of the common carotid artery

Origem e distribuição do plexo braquial de Saimiri sciureus

Os autores descreveram a origem e composição do plexo braquial de quatro Saimiri sciureus, pertencentes ao Centro Nacional de Primatas (Cenp), Ananindeua/PA, os quais foram fixados com formaldeído e dissecados. Os achados revelaram que o plexo braquial desta espécie é constituído por fibras neurais provenientes da união das raízes dorsais e ventrais das vértebras cervicais C4 a C8 e torácica T1, e organizado em quatro troncos. Cada tronco formou um nervo ou um grupo de nervos, cuja origem variou entre os animais; na maioria, foi encontrado o tronco cranial originando o nervo subclávio, o tronco médio-cranial dando origem aos nervos supraescapular, subescapular, parte do radial, e em alguns casos ao nervo axilar, nervo musculocutâneo e ao nervo mediano; o tronco médio-caudal formou parte do nervo radial, e em alguns casos os nervos axilar, nervo musculocutâneo, nervo mediano, nervo toracodorsal, nervo ulnar e nervo cutâneo medial do antebraço, sendo os dois últimos também originados no tronco caudal

Terrestrial behavior in titi monkeys (Callicebus, Cheracebus, and Plecturocebus) : potential correlates, patterns, and differences between genera

For arboreal primates, ground use may increase dispersal opportunities, tolerance to habitat change, access to ground-based resources, and resilience to human disturbances, and so has conservation implications. We collated published and unpublished data from 86 studies across 65 localities to assess titi monkey (Callicebinae) terrestriality. We examined whether the frequency of terrestrial activity correlated with study duration (a proxy for sampling effort), rainfall level (a proxy for food availability seasonality), and forest height (a proxy for vertical niche dimension). Terrestrial activity was recorded frequently for Callicebus and Plecturocebus spp., but rarely for Cheracebus spp. Terrestrial resting, anti-predator behavior, geophagy, and playing frequencies in Callicebus and Plecturocebus spp., but feeding and moving differed. Callicebus spp. often ate or searched for new leaves terrestrially. Plecturocebus spp. descended primarily to ingest terrestrial invertebrates and soil. Study duration correlated positively and rainfall level negatively with terrestrial activity. Though differences in sampling effort and methods limited comparisons and interpretation, overall, titi monkeys commonly engaged in a variety of terrestrial activities. Terrestrial behavior in Callicebus and Plecturocebus capacities may bolster resistance to habitat fragmentation. However, it is uncertain if the low frequency of terrestriality recorded for Cheracebus spp. is a genus-specific trait associated with a more basal phylogenetic position, or because studies of this genus occurred in pristine habitats. Observations of terrestrial behavior increased with increasing sampling effort and decreasing food availability. Overall, we found a high frequency of terrestrial behavior in titi monkeys, unlike that observed in other pitheciids