Thorax and Abdominal Muscles OIA's

Question 1

Rectus Abdominus OIA’s

Answer 1

Origin: pubic crest
Insertion: xiphoid process and costal cartilages of ribs 5-7
Action Compresses abdominopelvic cavity and flexes vertebral column

Question 2

External Oblique OIA’s

Answer 2

Origin: Lower 8 ribs
Insertion: linea alba and anterior iliac crest
Action: compresses abdominopelvic cavity, flexes and rotates vertebral column

Question 3

Internal Oblique OIA’s

Answer 3

Origin: inguinal ligament, iliac crest and lumbodorsal fascia
Insertion: linea alba, pubic crest and lower ribs
Action: compresses abdominopelvic cavity, flexes and rotates vertebral column

Question 4

Transverse abdominus OIA’s

Answer 4

Origin: Thoracolumbar facia, iliac crest and cartilages of lower ribs
Insertion: linea alba and pubic crest
Action: compresses abdominopelvic cavity

Question 5

External Intercostals OIA’s

Answer 5

Origin: inferior border of each rib
Insertion: superior border of rib below
Action: elevates ribs

Question 6

Internal Intercostals OIA’s

Answer 6

Origin: Superior border of each rib
Insertion: inferior border of each rib
Action: depresses ribs

Question 7

Diaphragm OIA’s

Answer 7

Action: Elevates lower ribs, expands thoracic cavity for breathing