▁that ▁covers ▁both ▁legs ▁is ▁a ▁double ▁hip ▁sp ica . ▁A ▁one - and - a - half ▁hip ▁sp ica ▁enc ases ▁one ▁leg ▁to ▁the ▁an k le ▁or ▁foot ▁and ▁the ▁other ▁to ▁just ▁above ▁the ▁kne e . ▁The ▁extent ▁to ▁which ▁the ▁hip ▁sp ica ▁covers ▁the ▁tr unk ▁depends ▁greatly ▁on ▁the ▁injury ▁and ▁the ▁sur geon ; ▁the ▁sp ica ▁may ▁extend ▁only ▁to ▁the ▁nav el , ▁allowing ▁mob ility ▁of ▁the ▁sp ine ▁and ▁the ▁possibility ▁of ▁walking ▁with ▁the ▁aid ▁of ▁cr ut ches , ▁or ▁may ▁extend ▁to ▁the ▁rib ▁c age ▁or ▁even ▁to ▁the ▁ar mp its ▁in ▁some ▁rare ▁cases . ▁H ip ▁sp icas ▁are ▁common ▁in ▁maintain ing ▁reduction ▁of ▁fem oral ▁f ract ures ▁and ▁are ▁also ▁used ▁for ▁con gen ital ▁hip ▁dis loc ations , ▁mostly ▁while ▁the ▁child ▁is ▁still ▁an ▁infant . ▁ ▁In ▁some ▁cases , ▁a ▁hip ▁sp ica ▁may ▁only ▁extend ▁down ▁one ▁or ▁more ▁legs ▁to ▁above ▁the ▁kne e . ▁Such ▁cast s , ▁called ▁p antal oon ▁cast s , ▁are ▁occasionally ▁seen ▁to ▁imm obil ize ▁an ▁injured ▁lum bar ▁sp ine ▁or ▁pel vis , ▁in ▁which ▁case ▁the ▁tr unk ▁portion ▁of ▁the ▁cast ▁usually ▁extends ▁to ▁the ▁ar mp its . ▁ ▁M ob ility ▁and ▁h yg iene ▁M ob ility ▁is ▁sever ely ▁restricted ▁by ▁the ▁hip ▁sp ica ▁cast ▁and ▁walking ▁without ▁cr ut ches ▁or ▁a ▁walk