Major variations in branching patterns of the external carotid artery (3 types) and variations in the confluence of the facial, lingual, and superior thyroid veins with internal jugular vein (5 types)

Variant Type	Description
Arterial
Noncommon trunk	Facial, lingual, and superior thyroid arteries arise separately from the ECA
Truncus linguofacialis	Facial and lingual arteries arise from the ECA in a common trunk
Truncus thyrolingualis	Superior thyroid and lingual arteries arise from the ECA in a common trunk
Venous
Thyrolinguofacialis	Facial, lingual, and superior thyroid veins form a thyrolinguofacialis vein
Linguofacialis	Facial and lingual veins form a venous stem
Thyrofacialis	Facial and superior thyroid veins join together, and separate lingua l vein joins into the IJV
Nonfacial vein	Superior thyroid and lingual veins join together into the IJV
Separation	Lingual and superior thyroid veins fuse independently with the IJV

Note:—ECA indicates external carotid artery; IJV, internal jugular vein.