The anatomical location of the great saphenous vein at the thigh and ankle: a neonatal cadaver study

Providing critically ill neonatal patients with parenteral nutrition, medication, fluids, and ac - cess to blood sampling is essential in intensive care units. One option for blood sampling is the great saphenous vein within the proximal thigh, and near the medial malleolus in neonates via 'conventional' landmark and ultrasound techniques. Practitioners in many countries still use the traditional landmark approach to locate the great saphenous vein in neonates, regardless of access to ultrasound. We aim to provide measurements that accurately describe the anatomy of the great saphenous vein in neonates to aid in cannulation success. The great saphenous vein was exposed in the proximal thigh and near the medial malleolus by reflecting the skin in 31 and 30 formalin-fixed ne - onate cadavers, respectively. Pins were placed at essential bony landmarks and soft tissue structures. The termination of the great saphenous vein within the proximal thigh can be located 6.8 +/- 1.5 mm inferior to the inguinal ligament. The average shortest distance from the medial malleolus to the great saphenous vein was 4.3 mm, 2.0 mm anterior, and 3.1 mm superiorly. The diam - eter of the great saphenous vein in the proximal thigh and at the medial malleolus ranged between 1.4 mm and 1.6 mm, and 0.9 mm and 1.1 mm, respectively with a 95% confidence level. Our re - sults provide a more accurate description to gain venous access through the great saphenous vein. However, if available, ultrasound should be used to locate and confirm the diameter of the great sa - phenous vein in the lower limb.