Non satellite veins in the pelvic limb of the llama (Lama glama)

Abstract

The objective of this study was to determine the major differences in the venous system of the pelvic limb of the llama (Lama glama) and that of other mammals, including humans. Eight adult llamas, preserved by means of 6% formalin solution at 0°C, were dissected. The venous system was perfused with a solution of 17% coloured industrial gelatin. Two venous systems are recognised, superficial and deep. The veins of the deep system follow the same course as the arteries, except for two important veins located in the femoral, popliteal and crural regions. A more voluminous vein than the femoral originates in a venous tripod in the proximal part of the femoral canal and forms an anastomosis with the femoral vein distally. The popliteal vein gives off an expansion located along the popliteal region. In the leg, it continues with a vein that accompanies the tibial nerve and forms an anastomosis distally with the medial saphenous vein. The described venous distribution represents an interesting complement to the medial saphenous, popliteal and femoral veins, being more important than the last one for its volume. In the thigh it would correspond to the deep femoral vein as in humans and dogs; the homology in the popliteal and leg regions is too difficult because it probably corresponds to the caudal tibial vein of the human, the caudal branch of the medial saphenous vein, and the satellite vein of the tibial nerve in the horse. Anat Rec 256: 99-103, 1999. 1999 Key words: venous system; llama; pelvic limb; comparative anatomyThe llama (Lama glama) is a South American cud-chewing mammal related to camels but smaller and without a hump. It was domesticated in the Andes and has been used as a beast of burden and a source of food. Literature about the venous system of the pelvic limb of the South American Camelidae is scarce. The authors have been studying the arterial system for the last few years, (Graziotti et al., 1997a(Graziotti et al., ,b, 1998 and have now begun a study of the venous system.The venous system of the pelvic limb of the llama consists of a superficial and deep set of veins. Superficial veins follow the same general course as the arteries. However, the deep set is different and is described for the first time by the authors; it is formed by two important veins located in the femoral, popliteal and crural regions. Domestic species and humans do not have this venous pathway, except for partial homologies. MATERIALS AND METHODSThis research was conducted on eight postmortem specimens different in sex, age and origin, which were destined for slaughter. They were perfused by arterial irrigation using the no. 18 Levine type catheter, from the abdominal aorta with a 6% unbuffered formalin solution; then they were preserved at 0°C. The venous system was filled, using a K 35 catheter, via palmar proper digital III vein with 17% coloured industrial gelatin solution in water. The systematic dissection was made with traditional working techniques using standard instruments. RESULTS Thigh RegionWithin the fem...