The document describes the major abdominal muscles. The rectus abdominis muscle has vertical fibers and flexes the trunk. The external oblique muscle has diagonally placed fibers and flexes and rotates the trunk to the opposite side. The internal oblique also has diagonally placed fibers and flexes and rotates the trunk to the same side. The transversus abdominis has transverse fibers and compresses the abdomen.

1. ABDOMINAL THEORY

2. SUPERFICIAL MUSCLES
 RECTUS ABDOMINUS –
Abdominal muscles with
vertical fibers
 Origin –Pubic crest and
Pubic symphysis
 Insertion-Costal cartilages
of ribs 5 to 7,xiphoid
process of sternum
 Movements-Trunk
flexion,Assists in trunk
rotation,trunk lateral flexion

3.  EXTERNAL OBLIQUE
– Diagonally placed
muscle fibers lateral to
medial
 Origin – External
surface or Ribs 5th to
12th
 Insertion – Anterior illiac
crest and abdominal
aponeurosis
 Movements-Trunk
lateral flexion and Trunk
rotation to opposite side

4.  INTERNAL OBLIQUE –
Diagonally placed muscle
fibers medial to lateral
 Origin-Illiac
crest,Thoracolumbar fascia
 Insertion- Costal cartilages of
ribs 8 to 12 and abdominal
aponeurosis
 Trunk lateral flexion and Trunk
rotation to same side

5. Deep muscles
TRANSVERSUS
ABDOMINUS – Tranversely
placed muscle fibers of
abdominals
Origin –Anterior illiac
crest,Thoracolumbar fascia
and cartilages of ribs 6 to 12
Insertion-abdominal
aponeurosis,xiphoid process
and pubic symphysis
 Movements-Forced
expiration,Abdominal
compression

6. Pelvic floor muscles