23. Comparison of upper and lower three-fourths of
anterior abdominal wall
Upper Midline Lower Midline
Linea alba well developed Linea alba poorly developed
Right and left recti well separated Right and left recti close together
Anterior and posterior layers of sheath
present
Only anterior layer of sheath present
Aponeurosis of external oblique weak or
absent
Aponeurosis of external oblique strong
and well developed