Abdominal muscles:
Abdominal muscles
Anterior Lateral Posterior
rectus abdominis m. external oblique m. quadratus lumborum
m.
pyramidalis m. internal oblique m.
psoas major m.
transversus abdominis m.
psoas minor m.
Common actions of abdominal m.:
• Make up intra-abdominal pressure – compress abdomen – important for fixation of
internal organs
• Helps in evacuation processes – defecation, urination, childbirth
1. Anterior abdominal m. - flex vertebral column
Rectus abdominis m.
Paired (right & left)
A long m. that extends the entire length of the ant. abdominal wall
Origin: pubic crest & pubic symphysis
Insertion: cartilages of ribs 5 – 7 & xiphoid process of sternum
Ant. surface of the m. is interrupted by 3 transverse fibrous bands of tissue
– tendinous intersections – divides the m. into 4 –5 bellies (specific
characteristic)
, Covered by the rectus sheath (specific characteristic) – formed by the
aponeuroses of lateral abdominal m. - consists of:
1. Anterior layer/lamina
▪ totally covers anterior surface of rectus abdominis m.
▪ formed by the aponeuroses of external & internal oblique
abdominis m.
2. Posterior layer/lamina
▪ covers superior 2/3rd of post. surface of rectus abdominis m.
▪ formed by the aponeuroses of internal oblique abdominis &
transversus abdominis m.
• Inferior boundary of posterior layer makes the arcuate line
• Lateral boundary of rectus sheath makes semilunar line
Abdominal muscles
Anterior Lateral Posterior
rectus abdominis m. external oblique m. quadratus lumborum
m.
pyramidalis m. internal oblique m.
psoas major m.
transversus abdominis m.
psoas minor m.
Common actions of abdominal m.:
• Make up intra-abdominal pressure – compress abdomen – important for fixation of
internal organs
• Helps in evacuation processes – defecation, urination, childbirth
1. Anterior abdominal m. - flex vertebral column
Rectus abdominis m.
Paired (right & left)
A long m. that extends the entire length of the ant. abdominal wall
Origin: pubic crest & pubic symphysis
Insertion: cartilages of ribs 5 – 7 & xiphoid process of sternum
Ant. surface of the m. is interrupted by 3 transverse fibrous bands of tissue
– tendinous intersections – divides the m. into 4 –5 bellies (specific
characteristic)
, Covered by the rectus sheath (specific characteristic) – formed by the
aponeuroses of lateral abdominal m. - consists of:
1. Anterior layer/lamina
▪ totally covers anterior surface of rectus abdominis m.
▪ formed by the aponeuroses of external & internal oblique
abdominis m.
2. Posterior layer/lamina
▪ covers superior 2/3rd of post. surface of rectus abdominis m.
▪ formed by the aponeuroses of internal oblique abdominis &
transversus abdominis m.
• Inferior boundary of posterior layer makes the arcuate line
• Lateral boundary of rectus sheath makes semilunar line
