Fig. (4) Schematic diagram of the carotid triangle of the neck
illustrating the variant origin of the superior thyroid artery (STA)
and superior laryngeal artery (SLA). Note that superior thyroid
artery (STA) is arising from the common carotid artery (CCA)
instead of external carotid artery (ECA). Similarly, superior
laryngeal artery (SLA) is originating from the external carotid
artery (ECA) instead of superior thyroid artery (STA). Internal
laryngeal nerve (ILN) which accompanies the superior laryngeal
artery (SLA) to pierce the thyrohyoid membrane is also shown.
(ICA- Internal carotid artery, TG- Thyroid gland, SCMSternocleidomastoid,
PD- Posterior belly of digastric).