"Side ribs" refer to the long, curved bones located on the sides of animals, especially pigs or cows. These ribs are usually used for cooking and are known for their tender meat and delicious taste. Full definition
Feel the stretch on the right side ribs and the waist region. (yogicwayoflife.com)
Without the press of the elbow against the knee you'll need to breath even more length into the lower side ribs. (fivepillarsyoga.com)
When I am feeling fearful about anything breast cancer - related, I will place my left hand over the tattoo (it's on my left side ribs) and breathe deeply. (health.com)