<prompt> If posterior epistaxis cannot be controlled, which artery is ligated -Posterior ethmoidal arteryMaxillary arterySphenopalatine arteryExternal carotid artery  <response>: 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 arteryInternal maxillary arteryExternal carotid ArteryAnteriorposterior ethmoidal arteryEarlier 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 ESPALIt is the most popular procedure for ligation and has replaced internal maxillary artery ligation.Can be done under LAGAIncision is given 8 mm anterior and under the posterior end of middle turbinateSphenopalatine artery is ligated in the sphenopalatine foramenQSuccess rate 100Complications very rare rebleeding, infection and nasal adhesionsInternal Maxillary Artery LigationEarlier 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 ligatedQSuccess rate 89Complications 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. 