True regarding surface anatomy of internal jugular vein -
SURFACE MARKINGS OF IMPORTANT VESSELS OF NECK
Surface anatomy of internal jugular vein:

Internal jugular vein is marked by a line joining a point on the neck, medial to the ear lobule to a point at the medial end of the clavicle

Surface anatomy of the external jugular vein:

Marked by a line joining a point a little below and behind the angle of the mandible to a point on the clavicle just lateral to the posterior border of the sternocleidomastoid.

Common carotid artery:

Marked by a line joining a point on the sternovlavicular joint to a point on the anterior border of the sternocleidomastoid at the level of upper border of the thyroid cartilage.

Internal carotid artery:

Marked by a line joining a point on the anterior border of the sternocleidomastoid at the level of upper border of thyroid cartilage to a point on the posterior border of the condyle of the mandible.

External carotid artery:

Marked by a line joining a point on the anterior border of the stemocleidomastoid at the level of upper border of thyroid cartilage to a point on the posterior border of the neck of the mandible.
Line passing from ear lobule to mid point of clavicle
Line passing from ear lobule to medial end of clavicle
Line joining ear lobule to lateral end of clavicle
Line joining mastoid process to mid point of clavicle