It is derived from the aponeurosis of the abdominal external oblique muscle.

The abdominal external oblique muscle attaches to the iliac crest.

For the abdominal oblique muscle, see Abdominal external oblique muscle.

It affords attachment to the inguinal falx, and to the abdominal external oblique muscle and pyramidalis muscle.

The multifidus lies deep relative to the Spinal Erectors, Transverse Abdominus, Abdominal internal oblique muscle and Abdominal external oblique muscle.

The knee raise exercise will work the lower abdominals, and can also work the obliques (see abdominal external oblique muscle and abdominal internal oblique muscle) if you twist your torso during the exercise.