Thus, {TAIL ~ the plug board} may be rigidly supported by {HEAD ~ the upper and lower housings} 
Thus , { TAIL ~ the plug board } may be rigidly supported by { HEAD ~ the upper and lower housings }
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD