- Usually refers to the rectus abdominis, a large muscle in the front of the abdomen that assists in the regular breathing movement and supports the muscles of the spine while lifting and keeping abdominal organs such as the intestines in place. The rectus abdominis plays a key role in "sit-ups." Rectus means straight. The rectus abdominis is a straight abdominal muscle.
* * *1) any of several straight muscles (as the rectus abdominis or the rectus femoris)2) any of four muscles of the eyeball that arise from the border of the optic foramen and run forward to insert into the sclera of the eyeball:a) one that is the thinnest and narrowest and inserts into the superior aspect of the sclera called also rectus superior, superior rectusb) one that is the longest, arises by two heads, and inserts into the lateral aspect of the sclera called also lateral rectus, rectus lateralisc) one that is the broadest and inserts into the medial aspect of the sclera called also medial rectus, rectus medialisd) one that inserts into the inferior aspect of the sclera called also inferior rectus, rectus inferior
* * *n.any of several straight muscles. The rectus muscles of the orbit are some of the extrinsic eye muscles. Rectus abdominis is a long flat muscle that extends bilaterally along the entire length of the front of the abdomen. The rectus muscles acting together serve to bend the trunk forwards; acting separately they bend the body sideways. The rectus femoris forms part of the quadriceps.
* * *rec·tus (rekґtəs) [L.] straight; anatomical terminology for a straight structure, such as a muscle (see entries beginning musculus rectus).
Medical dictionary. 2011.