<s>[INST] context: Ligation technique is reserved for intractable bleeding where the source cannot be located or controlled by other techniques.
The hierarchy of arteries used for ligation is:

Sphenopalatine artery
Internal maxillary artery
External carotid Artery
Anterior/posterior ethmoidal artery


Earlier the most common artery ligated was maxillary artery but now endonasal sphenopalatine artery ligation (ESPAL) is the ligation of choice.

“ESPAL is the current ligation of choice controlling bleeding in over 90% of cases with a low complication rate.”
Transnasal Endonasal Sphenopalatine Ligation (TESPAL or ESPAL)

It is the most popular procedure for ligation and has replaced internal maxillary artery ligation.
Can be done under LA/GA
Incision is given 8 mm anterior and under the posterior end of middle turbinate
Sphenopalatine artery is ligated in the sphenopalatine foramenQ
Success rate ~100%
Complications very rare – rebleeding, infection and nasal adhesions

Internal Maxillary Artery Ligation

Earlier it was the ligation procedure of choice for uncontrolled bleeding:
Internal maxillary artery is ligated in the pterygopalatine fossa using a Caldwell-Luc approach (3rd part of the artery is ligated)Q
Success rate – 89%
Complications – Sinusitis, damage to infraorbital nerve, oroantral fistula, dental damage and anesthesia, and rarely ophthalmoplegia and blindness.

External carotid artery ligation and anterior and posterior ethmoidal artery ligation is not commonly done. [/INST] question: If posterior epistaxis cannot be controlled, which artery is ligated - | options: A: Posterior ethmoidal artery B: Maxillary artery C: Sphenopalatine artery D: External carotid artery | answer: C </s>