On Earth, people have occasionally been spotted with backwards blood flow in the left internal jugular vein if there is a blockage lower down, such as from a tumour growing in their chest ...

The internal jugular vein is located in the carotid sheath in the neck, alongside the vagus nerve and carotid arteries. It runs down the left and right sides of the neck, delivering blood from the ...

2. Ascher E, Salles-Cunha S, Hingorani A. Morbidity and mortality associated with internal jugular vein thromboses. Vasc Endovascular Surg 2005;39:335-339.