Picture of the ribcage
The ribcage, also called the thoracic cage, is a bony structure made up of the rib bones and their connective tissues. The ribcage forms part of the body’s respiratory system. It enables expansion of the chest cavity so that the lungs can expand and breathe in oxygen. The ribcage also encloses the thoracic cavity and helps protect the heart and lungs from damage.
There are 24 ribs in the human body, divided into two sets of 12 curved, flat bones. Each one is attached by cartilage at the back to the thoracic vertebrae. The first upper seven ribs are known as 'true ribs' and are directly attached by cartilage to a long flat bone at the centre of the chest called the sternum (breastbone). The remaining pairs of ribs are known as ‘false ribs’. The eighth, ninth and tenth ribs are also attached to the sternum but not directly. The eleventh and twelfth ribs are called 'floating ribs' as they are not directly attached to the sternum. Some people are missing these ribs, while others may have an extra set.
How many ribs do men and women have?
While there are variations on the number of ribs, both men and women generally have the same number of 24 ribs. This discovery in the 14th century sparked a wave of controversy as it was at odds with the Biblical story of Adam and Eve, which claimed Eve was formed from Adam’s rib, suggesting men should have one less rib than women. Men’s ribcages are usually larger than women’s as testosterone during puberty triggers expansion of the rib cage to allow for better oxygen inhalation.
Conditions affecting the ribcage include:
- Bruised, cracked or fractured ribs - the most common condition affecting the rib cage.
- Flail chest - a potentially serious condition where more than one rib is fractured and can affect expansion of the ribcage and ability to breathe.
- Pectus excavatum - sunken chest is a congenital deformity where several ribs grow abnormally.
- Pectus carinatum - also known as pigeon chest, a deformity that causes the sternum and ribs to stick out.
- Bifid or bifurcated ribs - a congenital deformity where the end of the rib is split in two at the sternum.
- Sternal fracture - relatively uncommon and linked with severe trauma. This can be fatal due to associated heart or lung injuries.
- Rib removal - this can be done surgically for cosmetic or therapeutic reasons.
- Cervical rib - where an extra rib occurs on one or both sides and can cause nerve problems in the arm.