Noun
A straight muscle; as, the recti of the eye.
Source: Webster's dictionaryA center with a clockwise sense of rotation is an R or rectus center and a center with a counterclockwise sense of rotation is an S or sinister center. Source: Internet
Because other cases are very rare, the forms of the status rectus are known only by isolated numerals. Source: Internet
The basic form of the noun is the status rectus (the Governed state), which is the form as described above, complete with case endings. Source: Internet