Each side rail portion has {TAIL ~ a downwardly extending mid wall} between the outer wall and the inner wall for supporting {HEAD ~ the foot support member} 
Each side rail portion has { TAIL ~ a downwardly extending mid wall } between the outer wall and the inner wall for supporting { HEAD ~ the foot support member }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD