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.