thorax and abdominal muscles

rectus abdominus

nothing

rectus abdominus origin:

pubic crest

rectus abdominus insertion

xiphoid process and costal cartilage of ribs 5-7

rectus abdominus action

compresses abdominopelvic cavity and flexes vertebral column

external oblique

nothing

external oblique origin

lower 8 ribs

external oblique insertion

linea alba and anterior iliac crest

external oblique action

compresses abdominopelvic cavity, flexes and rotates vertebral column

internal oblique

nothing

internal oblique origin

inguinal ligament, iliac crest, and lumbodorsal fascia

internal oblique insertion

linea alba, pubic crest, lower ribs

internal oblique action

compresses abdominopelvic cavity, flexes and rotates vertebral column

transverse abdominus

as it is the deepest layer of the abdominal wall muscles

transversus abdominus origin

thoracolumbar fascia, iliac crest, and cartilages of lower ribs

transversus abdominus insertion

linea alba and pubic crest

transversus abdomninis action

compresses abdominopelvic cavity

external intercostals

nothing

external intercostals origin

inferior border of each rib

external intercostals insertion

superior border of rib below

external intercostals action

elevates ribs

internal intercostals

nothing

internal intercostals origin

superior border of each rib

internal intercostals insertion

inferior border of rib above

internal intercostals action

depresses rib

diaphragm action

elevates lower ribs, expands thoracic cavity for breathing

linea alba

a fibrous band of connective tissue running down the middle of the abdomen

lumbodorsal/thoracolumbar fascia

nothing

tendinous intersections

nothing

rectus sheath

a strong, fibrous compartment made of connective tissue that encloses the rectus abdominis ("six-pack") and pyramidalis muscles