It can also break a rib if properly struck. Use knife hand, side kick or closed fist for best results. Good stiff finger kife hand into this area works best. Use closed fist or front kick. Or a knee drop if attacker on the ground.
Elbow strike works best.
If position enables you a knee drop direct to the spine is very effective also. Closed fist, knife hand or elbow strike. Grab attackers hand with both of your hands, get a firm grip. Step backwards while pushing his wrist back up towards him. Do this quickly and you can break attackers wrist or at least bring him to the ground in a submission move.