The retromandibular and posterior auricular veins join at the angle of the mandible to form the external jugular vein, which runs inferiorly in the subcutaneous tissue of the anterolateral neck ...

Thus, the vein was probably enlarged because David was in an adrenaline-fueled situation, before facing the giant Goliath. The external jugular vein also appears in another sculpture by Michelangelo: ...

The jugular veins drain blood from the head. There are internal and external branches. The internal jugular vein lies deep in the root of the neck, medial to the sternomastoid muscle (Fig 1). It is ...