The application of {HEAD ~ vacuum} draws mucosal tissue against {TAIL ~ the carrier} and prevents movement of the sphincter region while the electrode penetrates tissue 
The application of { HEAD ~ vacuum } draws mucosal tissue against { TAIL ~ the carrier } and prevents movement of the sphincter region while the electrode penetrates tissue
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH