▁lig ament ▁of ▁the ▁kne e - joint , ▁from ▁which ▁it ▁is ▁separated ▁by ▁a ▁b urs a , ▁and ▁is ▁inserted ▁into ▁the ▁upper ▁part ▁of ▁the ▁med ial ▁surface ▁of ▁the ▁body ▁of ▁the ▁tib ia , ▁nearly ▁as ▁far ▁forward ▁as ▁its ▁anterior ▁cr est . ▁ ▁The ▁sem it end inos us ▁is ▁more ▁super f icial ▁than ▁the ▁sem im emb ran os us ▁( with ▁which ▁it ▁shares ▁very ▁close ▁insert ion ▁and ▁attachment ▁points ). ▁ ▁However , ▁because ▁the ▁sem im emb ran os us ▁is ▁wider ▁and ▁fl atter ▁than ▁the ▁sem it end inos us , ▁it ▁is ▁still ▁possible ▁to ▁pal p ate ▁the ▁sem im emb ran os us ▁directly . ▁ ▁At ▁its ▁insert ion ▁it ▁gives ▁off ▁from ▁its ▁lower ▁border ▁a ▁prolong ation ▁to ▁the ▁deep ▁fas cia ▁of ▁the ▁leg ▁and ▁lies ▁behind ▁the ▁tend on ▁of ▁the ▁s art or ius , ▁and ▁below ▁that ▁of ▁the ▁g rac ilis , ▁to ▁which ▁it ▁is ▁un ited . ▁ ▁These ▁three ▁tend ons ▁form ▁what ▁is ▁known ▁as ▁the ▁pes ▁an ser inus , ▁so ▁named ▁because ▁it ▁looks ▁like ▁the ▁foot ▁of ▁a ▁go ose . ▁ ▁Inner v ation ▁A ▁lower ▁motor ▁neur on ▁ex its ▁to ▁the ▁sac ral ▁p lex us ▁exit ing ▁through ▁the ▁sp inal ▁levels ▁L 5 - S 2 . ▁ ▁From ▁the ▁sac ral ▁p lex us , ▁the ▁lower ▁motor ▁neur on ▁travel s ▁down