Abdominal Wall Muscles Flashcards
What are the 4 main abdominal wall muscles?
External oblique
Internal oblique
Transverse abdominis
Rectus abdominis
What is an aponeurosis?
Flattened tendon like structure which i a connective tissue support for muscles in the abdominal region
What is the origin and insertion of External oblique?
Origin = 5-12th ribs
Inserts = Iliac crest, Inguinal ligament and linea alba
Hat is the function of external oblique?
Flexes the trunk
Rotates core to opposite side (since fibres run inferno medially)
What is the origin and insertion of internal oblique?
O = Inguinal ligaments, iliac crease and thoracolumbar fascia
I = lower ribs and linea alba
What is the action of internal oblique?
Compresses abdominal viscera
Flexes the trunk
Rotates core to same side
What is the origin and insertion of the transverse abdominis?
O = lower ribs, thoracolumbar fascia, iliac crest and Inguinal ligament
I = linea alba and pubic crest
What is the action of transverse abdominis?
Compresses abdominal contents and contributes to core stability
(Fibres run horizontally/transversely)
What is the origin and insertion of Rectus abdominis?
O = pubic crest
I = ribs and xiphoid process
What is the Rectus sheath?
The aponeurosis of the lateral muscles surrounding the Rectus abdominis
These muscles include external and internal obliques, along with the transverse abdominis
Where is the arcuate line?
About half way between umbilicals and pubic symphysis
How does the Rectus sheath differ when its above and below the arcuate line?
Above the arcuate line the Rectus sheath surrounds Rectus abdominis completely
Below the arcuate line the Rectus sheath is anterior to the Rectus muscles, on the posterior side is the transversalis fascia and parietal peritoneum
What is the nerve supply to the 4 abdominal muscles?
Lower thoracic spinal nerves (T7-T12)
Internal oblique and transverse abdominis also get supply from L1
