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