a) inserting {HEAD ~ the end effector} into {TAIL ~ the mouth} of a patient and translating the end effector to the esophagus or the stomach of the patient 
into
a ) inserting { HEAD ~ the end effector } into { TAIL ~ the mouth } of a patient and translating the end effector to the esophagus or the stomach of the patient
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH