▁sh aft ▁angle ▁beyond ▁ 9 0 ▁degrees . ▁It ▁is ▁most ▁commonly ▁a ▁sequ ela ▁of ▁o ste ogen esis ▁imper fect a , ▁P ag ets ▁disease , ▁o ste omy el itis , ▁tum our ▁and ▁tum our - like ▁conditions ▁( e . g . ▁f ibr ous ▁d ys pl asia ). ▁ ▁C ox a ▁var a ▁can ▁happen ▁in ▁cle id oc ran ial ▁d ys ost osis . ▁ ▁An atom y ▁In ▁early ▁ske let al ▁development , ▁a ▁common ▁phys is ▁serves ▁the ▁greater ▁tro chan ter ▁and ▁the ▁capital ▁fem oral ▁e pi ph ysis . ▁This ▁phys is ▁div ides ▁as ▁growth ▁continues ▁in ▁a ▁balance ▁that ▁fav ors ▁the ▁capital ▁e pi ph ysis ▁and ▁creates ▁a ▁normal ▁neck ▁sh aft ▁angle ▁( angle ▁between ▁the ▁fem oral ▁sh aft ▁and ▁the ▁neck ). ▁The ▁corresponding ▁angle ▁at ▁m atur ity ▁is ▁ 1 3 5 ▁ ± ▁ 7 ▁degrees . ▁Another ▁angle ▁used ▁for ▁the ▁measurement ▁of ▁co xa ▁var a ▁is ▁the ▁cer vic of em oral ▁angle ▁which ▁is ▁approximately ▁ 3 5 ▁degrees ▁at ▁inf ancy ▁and ▁increases ▁to ▁ 4 5 ▁degrees ▁after ▁m atur ity . ▁ ▁Types ▁ ▁Development al ▁ ▁primary ▁defect ▁in ▁end och ond ral ▁o ss ification ▁of ▁the ▁med ial ▁part ▁of ▁the ▁fem oral ▁neck ▁( M ost ▁common ▁cause ) ▁ ▁Ex cess ive ▁inter uter ine ▁pressure ▁on ▁the ▁developing ▁f etal ▁hip ▁