gemellus

noun

ge·​mel·​lus jə-ˈme-ləs 

plural gemelli -ˌlī  also gemelluses

: either of two small muscles of the hip that insert into the tendon of the obturator internus:

a

: a superior one originating chiefly from the outer surface of the ischial spine

called also gemellus superior

b

: an inferior one originating chiefly from the ischial tuberosity

called also gemellus inferior