I-elbow ye-90 luhlobo lwe-elbow ene-angle ye-90 degrees, isetyenziselwa ukutshintsha indlela yokuhamba kombhobho. Ngokuqhelekileyo isetyenziswe kwiinkqubo zemibhobho apho ii-angles zokugoba ezingqongqo zifunekayo, njengaxa ezinye izixhobo zepayipi kufuneka zixhunywe ngaphambi okanye emva kokugoba.
