- Compresses internal organs

- Most superficial abdominal muscle 

- Origin: Last few ribs and thoracolumbar fascia 

- Insertion: Brim of pelvis, tuber coxae, linea alba

- Runs ventral to caudal

- Compresses internal organs

- Origin: Tuber coxae and ligaments

- Insertion: Caudal ribs, brim of pelvis, linea alba

- A small branch of this muscle forms the cremaster muscle of spermatic cord

- Runs ventral to cranial

- Compresses internal organs, flex spine

– Origin: Costal cartilages and sternum

– Insertion: Brim of pelvis

– Multiple “bellies” separated by tendons which makes it look like a 6 pack