International Journal of Morphology
versión On-line ISSN 0717-9502
ARZONE, Carlos Alberto et al. Cervical Venous Circuit of the Llama (Lama glama). Int. J. Morphol. [online]. 2008, vol.26, n.4, pp. 849-852. ISSN 0717-9502. doi: 10.4067/S0717-95022008000400012.
The neck región of the Llama (Lama glama) has several structural and functional particularities in comparison to the same región of other domestic mammals. Among them, it is noticeable a distinctive venous circuit whose descnption is the purpose of this study.In order to perform the study, the veins of the neck of ten adult, male, wool type llamas were dissected with conventional technique. Previously to dissection, the veins were filled with a repletive substance.The authors describe the morphology of a venous circuit in which external jugular vein (v. jugularis externa), vertebral vein (v. vertebralis), and intervertebral veins (vv. Intervertebrales) are the main participating vessels. The distinctive feature is the fact that the metameric anastomoses between the forenamed veins leads to a jugular-vertebral by pass.The existence of venous shunts provides a circuit of collateral circulation, diverting the blood mainly towards the external jugular vein. Grazing habits and the length of the neck suggest that the vascular structure previously described facilitates the venous return, contributing to the regional blood stream control.
Palabras clave : Neck veins; Veterinary Anatomy; New World Camelids.