lateral abdominal group

Question 1

external oblique

Answer 1

• origin: external surfaces of lower 8 ribs, TL fascia
• insertion: Linea alba, anterior half of iliac crest
• action: compresses abdominal contents,
• bilateral contraction flexes trunk
• unilaterally: laterally bends the trunk

Question 2

internal oblique

Answer 2

• origin: thoracolumbar fascia, iliac crest, lateral half of inguinal ligament
• insertion: lower 3 or 4 ribs, linea alba, pubic crest,(pectineal line)
• action: same as external oblique

Question 3

transversus abdominis

Answer 3

• origin: lower 6 ribs, thoracolumbar fascia, anterior iliac crest, lateral inguinal ligament
• insertion: linea alba, pubic crest and pecten of the pubis
• action: compression and rotation