<prompt> Surface anatomy for internal jugular veinEar lobule to medial third of clavicleEar lobule to middle third of clavicleEar lobule to lateral third of clavicleMastoid to third of clavicle  <response>: Internal jugular vein is marked by a broad line by joining these two points: a.The first point on the neck medial to the lobule of the ear b.The second point at the medial end of the clavicle. 